I think you will find that side effects vary depending on your surgery, (lumpectomy or mastectomy) and your type of skin. The common side effects are skin related and also some people feel tired towards the end of the treatment.
I have almost finished my radiotherapy and have had minimal skin irritation (see my post about radiation after mastectomy for info on skin care) and have not really felt that tired. I had mastectomy and 18 weeks chemo prior to radiation. Radiation has been a breeze compared to chemo!
Good luck with your treatment.
Deanne xx