Lumps in armpit after surgery

Thanks @Sue_w,
I did look at info on cording and while I can feel the 'line' where the lymph nodes have been removed, that's not what's worrying me, its a mass on the very side of my chest, right next to my armpit. It feels like firm muscle and is very tight, makes me feel like I'm constantly wearing a top with armholes that are too small. Doc did take some of the muscle/lining from the chest wall so it might just be where things have been rearranged and need time to settle into place.(hope the pic makes more sense as I'm struggling to describe it properly). 
I also have some small lumps under the armpit, my surgery was almost three week ago and I think they're forming because of irritation to the arm pit but can't find any reference to anything similar on here so I'm not sure. 
I am going to see my Doc next week and the Lymphoedema clinic so I can ask them then, just thought I'd see if anyone here had similar experiences.