Warmth in back? Not hot flashes...I had those, after Lupron shot

I was treated with IMRT from Oct-Dec 2019 for prostate cancer contained within----no spread. Had one Lupron shot (to last 6 months---tho I am aware there may still be some side effects past that, for awhile) before the radiation treatments began. The shot was in early Oct. I had the usual hot flashes over time, that would come over me in a wave, but those have dwindled inthe past couple of months. I still have one now and then, but rarely.
However, within the past couple of months, I have had a warmth come over my upper back.. It started, just occasionally, with just a small area up behind left shoulder, but then it progressed into nearly a constant feeling, and over much of my upper back area. It sometimes makes it hard for me to fall asleep, due to the constant warm feeling. Has anyone else experienced anything like this, after similar treatment plan?
By the way, I did get a good PSA reading of 0.1 about a month ago, so that felt good.
Thanks.