So weird you write this as I developed a swelling above my collar bone straight after my breast biopsy. It freaked me out and I had a bad panic attack when I noticed it. Anyway 5 months later after mastectomy and radiotherapy I still have this swelling and it aches. I have had ultrasound and CT and they can see the swelling but don't know why it is. Did you get your results?
Have they given you any idea when your results might come through? Its not a great time for biopsys and results, as of course as you know they will more than likely get delayed by the breaks that people took over Christmas. In theory above the collar bone lymph nodes could be affected by breast conditions (if its lymph nodes that are causing the swelling), including potentially infections. Its not unheard of for infections after biopsies. I would consider going back to your GP to show them the swollen area you have found, so they can reassess, maybe they might be able to contact the clinic and say that you have felt a change in the condition and push along the results a bit more quickly?