Thanks for writing in to Healthcare Magic!
The stone like sensation in the throat is due to intense inflammation.
You are having sore throat
and cause can be a bacterial or a viral infection.
The antibiotics are slow to act and so do not expect magic, it would start improving slowly.
To speed up it also ensure a good local hygiene-brush the teeth twice a day and rinse with chlorhexidine
application locally after saline mouth gargles thrice a day. You must take full course of penicillin.
If you have any further query please let me know I would try to answer it for you.
Wish you a great health!