Since your surgery you have been under tremendous stress. When your body is undergoing recovery from surgery of this kind, anxiety and depression can definitely undermine your recovery.
If Effexor can help bring you into more equilibrium it can definitely help your GI tract's adjustment.
I have heard of the use of SSRIs that Ashley is referring to. Since esophageal spasms and irritation have been part of your recovery difficulties, it would make sense that it might help you feel better.
It's certainly worth a try. It makes all kinds of sense.
Good luck...hope you find it makes a big difference!