Hi sir....   The bumps may be due to irritation from any sharp cusps

It is normal anatomy ,please stop putting finger  in that region of tongue .it causes gag .

Your cause of gag reflexes can be due to the irritation of the bumps on the posterior side of your tongue. It can be a stagnant infection which hasn’t gone totally which is leading to the bumps on your tongue or sore throat or an underlying condition. If you are smoking or eating tobacco or such things then stop it. Without a proper diagnosis and some test performed, coming to any conclusion is invalid. Please do visit an oral surgeon, he will do his best to treat you right. You are just 19 years old. Get treated on time. Good luck.