Help please.

Okay my son is 4 months old. We’ve been through every formula and 3 different types of reflux medicine before we found what helped. He’s on Nutramigen formula and Prevacid. I feel like I’ve become annoying to the pediatrician because I call often because my son has these screaming episodes that scare me. The doctor has checked him and told me that he is fine. But I feel like he would think differently if he saw the way my son acted during these episodes. My son will be smiling and giggling, and out of nowhere he will just let out the most gut wrenching screech! He screams so hard and so long that he can’t breathe, he chokes himself, and his eyes look like they’d pop out of his head. No matter what I do nothing helps. I’ve tried baths, fresh air, rocking, patting, car rides, feeding(he won’t even take a bottle), burping, diaper changes. NOTHING in the books help, I have timed it multiple times and it ranges from 20 min- 2 hours...... it’s scary and I don’t know what to do. I feel like he’s old enough now he shouldn’t be crying like this. He is always fussy even on his good days, but I’m getting so worn out on hearing my baby is okay when it seems like he’s in so much pain. Has any other mom been through this??