My son vomits 1 to 7 times a day. he does not feel sick before or after he vomits and has been doing this for several months and he has tried pepto bismol and nexium (esomeprazole) for acid.

Excessive : Excessive vomiting can cause a lot of problems, including electrolyte imbalances and damage to the teeth. 1-7 times per day for several months is definitely excessive. Your son needs to be evaluated by a physician. Assuming that this vomiting is not happening on purpose, he may have an obstruction in his gastrointestinal tract or a problem with the normal contractions of the stomach itself (called gastroparesis).