Is there a limit on money transfer between my own accounts ?
Yes you need to follow FEMA. There is some paperwork that needs to be done. As per FEMA [Foreign Exchange Management Act], any transfer by individuals outside of India need the 15CA & 15CB form. The 15CB is from a CA to state that taxes have been paid on the funds being transferred. The limit is 1 million USD per year.
Read more at Liberalized Remittance Scheme and here.
Since the money is already taxed in India , will I have to pay taxes again in US ?
There are no taxes. There maybe some reporting requirements on the tax returns in US.
Will I be faced with any queries from IRS ?
No if the returns are filed appropriately.