I was the same girls, no pain PO, using my arms as normal etc then suddenly week 3 my left boob was so painful with the same kinds of feelings like pulling and burning which lasted for a week then went away as quick as it came. Try not to worry about any pain that you get before 6 weeks because I also couldn’t see how I suddenly had pain and tightness at 3 weeks but now I’m nearly 6 weeks and feeling fine again with no concerns:) xx