For the past week or so my left breast has been feeling odd. It feels bigger then my right breast, for example if I stand up straight I can feel the left breast against my left arm and sometimes I can feel the extra skin under my armpit, Also had some mild pains as well. Ive also been experiencing cramp in my rib cage on the left side on the odd occasion not all of the time. Last week I was on holiday and I was sleeping on a hard bed so I dunno if that is the reason why for all of this. I have checked for any lumps on both of my breaths and have caught none, I am due to be on my period around this time. Can anyone give me a explanation for all of this? I am 22 and ive read theirs a very slim chance of me having cancer yet, but it`s at the back of my mind.