GERD Flareup - Caused by Ultram and Antibiotics?

Can Ultram and antibiotics cause GERD complications?  I was diagnosed with GERD in 1995 and have used PPI's for years (now using Nexium - 40mg).  I have taken Ultram for quite awhile for a wrecked knee (osteoarthritis).  Earlier this year, I started vomiting (just fluids or dry heaves) and didn't know why.  I had read somewhere that Ultram can cause bad long-term effects.  I tapered off the Ultram and no longer use it.  The vomiting stopped.  Recently, I had an ear problem and swollen lymph node below it, and the doctor prescribed an antibioltic (cephalasporin type).  As I used the antibiotic, each night I felt more upper abdominal pain.  I went back to the doctor, who checked me for heart or lung problems but found none.  She diagnosed me as having esaphageal spasms and prescribed Flexeril, a muscle relaxer.  Now I don't have much pain in the daytime but lying down at night causes me severe pain.  Could these medications have made my GERD worse?  I see my doctor on the 24th and wonder if I should request a higher dose of Nexium.  I don't have insurance and can't afford a bunch of very costly tests.  Sorry this was so long and complicated.  I'd appreciate any responses.