I agree with Deanne's interpretation of the statistics and second her suggestion to speak to your doctor if you are concerned.
Sandra it's very frustrating that you feel you weren't given enough information from your radiation oncologist. While I don't have pain or redness or any issues with my arm I do have an inverted nipple which still looks bruised 4 years later and part of my breast just feels "thicker" which is how my breast felt prior to me finding my lump. As I had a clear mammogram a few months before being diagnosed I have trouble ignoring this even though I have been assured it is from the radiation.
I was informed of these potential changes to my breast but I didn't really understand that it would feel to me like I was getting another tumour. That is the hard part - every time I do an exam I think "Yep this feels exactly the same as the few months before I found the lump!"
To be honest at the time of treatment I didn't really worry much about possible changes to my breast as the side effects I was more concerned about were the risks of heart damage (left side) and lung damage. I knew about the risk of second cancers but that risk is really quite small. I was given written information about these risks (it didn't include percentages though like my chemo information did) and I agree that everyone should be given written information about important details as there is just too much to remember.
I hope your doctors are able to answer your questions now.
