It is said that Parmatma is within me. And it is also said that prayer to any demigod or ghosts or spirits indirectly goes to Parmatma only.
So my question is : Can I pray to myself and receive the blessings of Parmatma ?
Yes, ... But ask to your(??)self who is praying? Parmatma or your psycho-physical existence? If psycho-physical existence wants to pray then to whom it wants to pray? And how would you know to whom you are praying? Other than Paramatma- you have mind as well? How will you ensure to pray to Paramatma only, not to the mind since you don't have any clue how Parmatma existing in you? Where you will find him/her(?) in the body to pray?????????? So, being a psycho - physical existence you can't pray to the Parmatma residing in you. This is the reason of existence of dualistic & semi-dualistic hindu philosophies.
But...Yes, there is a way to pray yourself but the way is such the sentence
there is a way to pray yourself too become a paradox. Because then you don't pray you just exist. You do so by become pure existence alone. You will then have to shift your ontology to Parabhairava state. Then the I is Shiva & the subjective feeling of the existence of I is Shakti. Then the prayer, the one who is praying, & the one whom you pray all become one. Lord Krishna said this Brahman Yajna. Brahma yajna is what you are looking for. But it is difficult to practice. In any case, this is the how you can pray to yourself - called Brahman Yajna. This is very deep & one of the most esoteric verse of Bhagvad Geeta, I would end up with verse only without commentary.
For those who are completely absorbed in God-consciousness, the oblation is Brahman, the ladle with which it is offered is Brahman, the act of offering is Brahman, and the sacrificial fire is also Brahman. Such persons, who view everything as God, easily attain him. BG-4.24
we say this in this way.
Whatever I take is offered to Lord Śiva. Whatever I have to offer is for Lord Śiva. Whatever I offer is itself Lord Śiva. I have to offer Lord Śiva in Lord Śiva.
Btw, you were not the first to ask this question. same question was asked long before, although in different ways.
The goddess said "Great lord, if such is the nature of the Supreme Sakti, then in the admittedly established rules of spiritual life, who would be invoked in recitation and what will be the recitation? Who, O great lord, would be meditated on, who would be worshipped, who is to be gratified ? V.Bhai-143
To whom is oblation to be offered? For whom is sacrifice to be performed ?' And how is it to be accomplished? V.Bhai- 144
Actually, Lord Shiva told Devi, everyone is Shiva alone, so Devi is asking then whome to worship, whom to offer etc (above questions). Which Lord Shiva answers in next verses.
That creative contemplation which is practised on the highest Reality over and over again is in this scripture japa (recitation in reality). That which goes on sounding spontaneously (inside) in the form of a mantra (mystic formula- "I ParAvAk" ) is what the japa is about. V.Bhai-145
Worship does not mean offering of flowers, etc. It rather consists in setting one's heart on that highest ether of consciousness which is above all thought-constructs! It really means dissolution of self with perfect ardour (in the Supreme Consciousness known as Bhairava). V.Bhai- 147
From Anuttarashtika by AcharArya Abhinavgupta:
In the oneness of that supreme state of anuttara what talk can there be, and what differentiated path of adorer, adored and adoration? To whom and by what means could a progression function; or what could constitute the succession of penetrating into the Self? Wonder of wonders! Though it appears differentiated this illusion is no other than consciousness–one without a second. Everything is nothing but the pure essence of your own Self-experience, so why worry in vain!
I can give you the answer according to the dualistic systems of Vedanta. Those are all the Vaishnava systems of Vedanta such as Dvaita, Vishishtadvaita, Acintya bheda abheda (Gaudiya Vaishnava), etc, because they teach the difference between jiva soul (jivatma) and paramatma.
If you pray to the paramatma within yourself that doesn't mean that you are praying to yourself! You are not the paramatma because you are the jivatma, so when you are praying to the paramatma which is within you that doesn't mean that you are praying to yourself! That means that you are praying to him, paramatma, and not to yourself (jivatma).
I explained earlier in my answer here why is there the difference between the two, jivatma and paramatma, and why we shouldn't mistake them as just one soul.
This difference is seen in the verses such as the Mundaka Upanishad 3.1.1:
Two birds, inseparable friends, cling to the same tree. One of them eats the sweet fruit, the other looks on without eating.
So, when you pray to the paramatma within yourself that means that you are praying to him, the other "bird" which is paramatma, and not to yourself (jivatma). Yes, you can do that, but Vaishnavas usually pray to the Lord Vishnu or Krishna who is that paramatma situated within you.
The lord resides in everyone's hearts, as Atma(आत्म) and hence can be prayed upon. If you pray to anyone (beings, ancestors, demons, deva-s), all worshipping reaches to the supreme one.
BG 10.17 - [Arjuna asked] -- O Yogi, how shall I think of You by remaining ever-engaged in meditation? And through what objects, O Lord, are You to be meditated on by me?
BG 10.20 - O Gudakesa, I am the Self(Atma) residing in the hearts of all beings, and I am the beginning and the middle as also the end of (all) beings.
Depending on what part of the self is prayed upon, one achieves it results.