Thanks @daffodil10 . 
With my exercises for mastectomy/lymph recovery, I found doing little movements, for a couple of minutes, throughout the day, just as good. I also did gentle stretches in bed, by holding my arm out, and above my head, as I watched TV. I did others sitting in a chair as I watched TV, or making meals etc.
Every exercise can be done little and often. After not being able to put my arm above my head, I can do this with no problems. But I got there gently. In a more natural way.
You can get weights that you wrap around your arms, feet. You can just put those on as you go about your day. They come in different levels. So there are ways round if you find a more focused weight training washes you out.
I do 300steps a day…. By going to the toilet after drinking so much…
. If someone told me to do 300 steps I’d think they were mad. 
Enjoy those treats