I kept the thought that after surgery, my cancer would be gone upper most in my mind. This helped me to feel positive about the mastectomy. I had very little pain, more a very tight feeling across the chest and under the arm (the cannula in my other hand hurt more!).
They will probably have a physio show you some exercises to help get full movement back in your arm. I did these often and had no trouble getting my arm moving well. I think they like you to get 75% of the movement back by about 6 weeks. I could drive after a week but had trouble reaching up for a while. So moving things you use a lot to bench height is a good idea.
I found Ahh Bras really good because you could pull them up rather than over your head at first. You can put your soft padding that you get from Berlei in them too.
In hospital I wore button up PJ's with loose singlet tops underneath. I had a bamboo one that was super soft against the skin. Easy to put on clothing is great for the first week or so. I wore leggings with the singlet top and then an oversize button up shirt over the top.
The hardest thing for me was sleeping on my back! I ended up with lots of soft pillows to get comfortable. I bought some dry shampoo because it is hard to wash your hair at first.
Hope this info helps. It was no where near as bad as I thought it would be so I hope you find the same. Take care. Deanne xxx