Painful breasts and lump

Hello, I discovered a lump last April. It was slightly painful and went to the GP. They put me on the two week pathway to the breast clinic. He said those famous words "cancerous lumps don't hurt, so that's a good sign".  I was sent for an ultrasound where I was told I had some breast thickening but all looked very normal. 

The lump has grown and is in my left breast. For the last four months I have gradually began to have pain in both breasts. Feeling very tender and too sore at times to wear a bra. The pain has began to wake me up at night. 

I have been back to the GP today and they have put me onto the breast clinic on the two week pathway again. She said it could be an infection or possibly a cyst but wanted to rule out anything else. She also said I could be peri menopausal. I am 39 so feel that's a possibility but I don't feel that's what's happening. 

I am a little worried as when I think back to when the symptoms began, it actually started with pain in my left side behind my breast. This was initially diagnosed with inflammation between rib muscles and then I was told it could be premenstrual angina. 

I worry that although pain isn't a listed symptom, many women have experiences where their breasts are painful and often wrongly diagnosed. Can anyone help with opinions on how to deal with health care professionals going forward. I know it may not turn out to be anything cancerous, however I feel I have maybe been fobbed off a little previously.