I have this same problem. It is pretty difficult to swallow food but I don't choke or anything, I just have to drink something after swallowing or else it just feels like the food slides down. Acid reflux, ulcers, and IBS along with anxiety could cause all this as it makes the swallowing mechanism tighten up as well as the muscles in our esophagus (anxiety makes us go into an adrenal state, which causes our digestive system to pretty much go crazy).
Any pain at all? I don't have any pain so I'm not so sure it's an ulcer, or if it is it has healed up and is just scar tissue causing the difficulty swallowing. Not sure, lol.