upset tummies

long post SORRY but i need help...

are there anyone with babies with sensitive tummies? any hidden reasoning behind it you found out after a while? my son will be 4 months in one week, and i am still trying to find a formula that "works" for him. He does have a reflux issue and he is also very constipated. I have tried everything from prune juice (his dr reccommended), essential oils for babies, tummy rubs, the leg motions, i vibrate him, bounce him, i use playtex bottles with the bags so he gets virtually NO air, i even have gotten him some formula that is already made so i do not have to shake it. No matter what it is that I do, he screams and screams in pain. Its not regular, sometimes he goes days without, and sometimes its for days on end. He has kept a constant temp of 99.8 for about 2/3 weeks but his doctor says he could be teething.. because EVERY time i take him to the dr he is happy as can be. He goes from laughing and smiling at me to holding his breath turning dark in the face to let out a massive scream. Ive taken him to my aunts, grandmothers, mother in law, my mom, I just dont know what to do to make my son feel better. Im crying typing because i feel horrible because i have to rock my screaming son and pat and bounce and whatever i can until he finally just falls asleep.

I am taking him to the dr again in the morning and demanding some sort of tests to be done, because there is no way he cant take any type of formula and he is having pains.

Dr says it is not colic, because he has not had these screaming pains since birth. Only started at the beginning of January.

Also he does sleep through the night, for the most part. when he finally lays down he may wake up often but he never cries for me until after about 8 hours and then the day repeats.

Like i said we are going to the doctor tomorrow. I just wanted to know if anyone had similar symptoms with their child and got answers.