Before I was diagnosed with breast cancer, I was diagnosed with fibromyalgia. What I found worked at that time is also helping me now. I get into hot water and do exercises. I used to swim laps in a hot water therapy pool. It made my fibromyalgia symptoms go away completely nearly. I was then diagnosed with IDC Her2+, estrogen+ stage 2a and had TCHP and a mastectomy without reconstruction.
I moved away from the area where that therapy pool is, and bought a house elsewhere in a rural location-no therapy pool nearby. I stopped doing the swimming and the symptoms returned.
Then, I bought an inflatable jacuzzi because I can't afford a pool. The water is kept at 99 degrees and I do exercises in it. The cardio and the hot water combined is what helped me.
If you can't do the hot water part, do the cardio part after you shower to loosen your muscles. Even if you don't do the shower part, the cardio is key. I went for brisk walks when my jacuzzi was broken, and that helped too.
I am now back to doing well with the fibromyalgia part of things, even though I have plenty of other issues including chemo brain and pain in my hands and feet from Tamoxifen. Do know that I am in pretty poor overall health with a heart condition, so I have to push myself to do anything, but this is really helpful, so I do it.
I hope this helps.