“Spotting and back pain?”

For years I have had horribly heavy periods and pains mid-cycle. I have had checks to see if I had fibroids or polycystic ovaries and that was all fine (this was about 4 years ago). But over the last few months, I now have had awful back pain both mid-cycle and when on. Mid-cycle I get abdominal pains and I think it's ovulation that I'm finding painful. This month, I have had spotting mid cycle too which I have never had before. It's a pinkish brown color. I'm also starting to get nausea and get very tired mid-cycle as well as when I'm on. Is this a cause for concern or am I just unlucky that ovulation seems to affect me? I don't know if these extra details make a difference but I am currently breastfeeding, these abdominal and back pains have become worse since having my daughter 18 months ago (although I have always had these pains) and the spotting is since having my second Pfizer jab which I heard can possibly affect periods.