Oral surgeon told me 80-90 % chances r that it could be a block in saliva gland n have to do a surgery.will that b a minor surgery?

Try this : I have had occasional success when a patient has a slightly blocked saliva duct ---> suck on a very sour lemon drop candy (the more sour, the better). Sometimes this creates enough saliva buildup that it pushes out the blockage (if small enough). If unsuccessful talk to the oral surgeon about the exact procedure and typical healing time.

Depends: Usually it is but depends where in the duct the stone is. The sooner it is done the less invasive it is.

Yes, usually.: Clearing a blocked salivary duct is usually a minor procedure.