Connection between past chemotherapy/radiation treatments and PMR now?

I am a 4 year triple negative breast cancer survivor who underwent 5 1/2 months of chemo and 28 radiation treatments. Yes, I am thankful I am a survivor and the treatment most likely saved my life, but I have never felt normal again since treatments.
I was wondering if there is any research that connects those type treatments to PMR now. To me it makes some sense as chemo is nothing more than chemical toxins that target cancer cells. I am not naive enough to believe those toxins don’t also attack the molecular makeup of normal healthy cells as well.
I have goggled a lot for, but have not found anything that remotely even talks about a possible connection.
Would love to hear from PMR patients who have had chemo to see if there could be a connection and it is just that nobody is looking into it.
Right now I am fairly new to PMR and tapering from 25mg of prednisone down to 15mg over a 4 month period of time. Hard to tell what is a PMR issue, a taper issue, a normal age related issue, and who knows what else issue. I almost feel like the side effects from chemo were more tolerable than PMR. With chemo I could plan around what days after treatment I would be jittery from steroids and when I would crash, what days I would have no sleep and what days I would do nothing but fall asleep, what days were filled with endless bathroom visits, and what days the fatigue would set in. With PMR I never know how I am going to feel and for how long I am going to feel that way.
Thanks for any input you may have.