Side effects radiation ?

Radiotherapy was ok but the day after it ended I joined a very gentle Stretch and Balance exercise program. My first class lasted one hour and most participants were well into their 70s .After class I went home and slept 4 hours I was wiped out. Engulfing tiredness has not persisted but other side effects have .I have had an infection requiring a lengthy course of antibiotics  , an inverted nipple which freaked me out as is a sign of cancer so off to doctor full check up - mammogram , ultrasound , needle biopsy all clear . Also my cancer was LHS deep in my chest above the heart and have had sharp chest pains also checked by ECG and declared ok.Radiotherapy can cause bone pain and I have had that in my ribs too. Whatever worries you get it checked out though .One of my annoyances about radiotherapy is I was never advised either by medical staff or the My Journey Kit of longer term side effects .