Hang in there. Radiation after surgery is very common because it does a "mop-up". A lot will depend on your pathology report post surgery on the tumor they took out. You will want to know if there is any evidence of perineural invasion, or if the tumor was HPV positive and sometimes the doctors don't say at first. I just asked for and got a copy of the pathology report so I could read it myself
I can't imagine any issue with radiation to your throat after radiation to your testicles. Heck I had radiation again on the exact same throat area even after the "maximum"
It's awful at first after the surgery but it does get better.
Keep the faith
Charm