At some point babies do need to learn how to go to sleep on their own, but at the same time they also need to know you are there for them if they need you, so it's a hard thing to balance.
There are all kinds of techniques, but not everything works for every baby, and the fact that your son has reflux makes it even harder. My son had it too, so he cried a lot, and he's a twin, so I always worried my daughter would not be able to sleep with him crying all the time, but she just got used to it. It is very hard to let them cry. At times one of us would go to our twins, but we did use the cry it out method, and it does work. You should start off with a shorter time period and gradually work up to a longer one. You can also stay in the room for a bit without going to him or talking, and slowly work your way out the door once it starts working. If you must go in, you can pat him on the back and tell him he's okay and then leave again. It does eventually stop, but you have to get through that initial difficult phase and break the cycle.
There were a few times when both of our kids were crying and it made me feel so bad that I went to another room so I could not hear it. When I came back, they were asleep. You have to remember that as long as they have been fed, diaper changed and are not sick or in danger, they are fine, and crying does not hurt them. We used pacifiers, and that helped a lot. I hope some of this helps a little.