It sounds like what my daughters went through. There is a kind of Gerd called silent reflux. http://infantrefluxdisease.com/infant_acid_reflux/silent-...
Clearly it's not silent (I say this in jest simply because I know how hard it is to have a baby crying in pain.) This just means that it's not obvious reflux because there's no spitting up.
Some drs don't prescribe meds for silent reflux because the baby is not loosing any weight. However, when the baby is having trouble sleeping and is in obvious pain all the time, meds may be the best thing. Long term Reglan causes bad issues so they have been prescribing Previcid instead. I had trouble administering the Prevacid tablets, though. Reglan and Zantac is what I gave my first two, and Prevacid to my third. They used to suggest adding cereal to the bottle, but they no longer do that (probably because early cereal has been linked to diabetes.) Instead they just say to feed often and in small amounts, and have her sit in the swing or bouncy seat after eating instead of laying her down flat. If you don't want her to get used to sleeping somewhere besides the bed, you can put a pillow or something under her mattress to raise one end, or raise the end of the crib.
The good news is that USUALLY babies outgrow it. For mine, they didn't even need to increase dosages of meds as they grew.
Symptoms my girls had:
Acted hungry even after having eaten or acted hungry, tried to eat, and then pulled away.
Cried more then usual (colic is evening crying, but reflux causes the baby to cry many times or all the time during the day.)
Had trouble sleeping, often waking crying.
Did not want to lie flat.
Arched back during or after feedings.
They put their hands in their mouth a lot. That's a common feeding cue and when the tummy hurts, putting the hand in the mouth is a good indication that either the child is hungry, teething, OR has reflux.