I too experienced little or no pain after a mastectomy. I also lost 17 lymph nodes and while my underarm belonged to someone else for a while, where there’s no feeling, there’s no pain! My mobility in the affected arm was very good. I did wear a bra, my original one as nothing impinged on the wound and I am large breasted. With a soft pad, I looked perfectly normal and was out and about in a matter of days. But wise to take it slowly, there’s a bit of body adjustment to make. Best wishes.