Pelvic pain, lower back pain, pain underarm/breast bone.. ?

Hi,

I've been having various symptoms now for a few months and I am worried that they may all be related and be a sign of something more serious.

I have been having lower back pack, abdominal pain and pelvic pain for months, and my lower back and pelvis is very imflammed. Initially I was just putting up with it, however after these symptoms worsened and I begun to bleed from the vagina (between period, very unusual for me) I became more concerned. Alongside this, I have had some changes to my skin pigmentation e.g. a light brown, flat mark on my left breast which has widened and a small very dark mole appear under my left arm. I have more recently had pain under my left ribcage and breast bone and my underarm is sore to touch.

I have had blood tests, swobs and internal examinations however nothing has been found apart from the fact that my pelvis appears imflamed. I am due to have an ultrasound next week however I am wondering if I need to push for further tests and what tests would be most appropriate? Is there a chance all of these symptoms are linked and if so, what could they be pointing towards??

Thank you