Who diagnoses cording?

Thanks Sister. On the left I can feel hard firm (like a bone or firm round rope or tube) non painful to touch long continuous areas below incision (not in) around to back below (not in armpit) and another one vertical up chest wall from top of incision beside armpit and up to beside shoulder area, When the drain was still in I thought was the drain under the skin. It's not like the small "piano strings" I have in the right armpit. Shall look for advice today.