If you're seeing spots in your throat, you may have an infection - particularly if you're running a fever. See your family doctor about that. I used to get that "thick throat" feeling too. As it turned out, it was caused by drainage from allergies. As long as I take allergy meds (particularly this time of year!) I have no trouble. GERD can also cause this feeling, so keep taking the protonix. There are other PPI meds that might work better for you like nexium or aciphex.
The anti-depressant wasn't prescribed for depression. Sometimes these meds can help with pain, which is why your doc wants you to try them. They are commonly used by pain management physicians for chronic pain patients. Sometimes it helps; sometimes not. Just one of those things that's worth a try.