I am glad your GP was horrified at the weights you were lifting! Were you 'dead lifting'? (I sure hope you weren't lifting anything above your shoulders!)
Frozen shoulder is incredibly painful & inconvenient @HelenlovesSnoopy and it usually just gets worse, rarely better, with or without physio. I had 18 months of physio, TENS machine, and even acupuncture - it all only got worse. :( That was 22 years ago, my left shoulder, which was corrected by manipulation under a block anaesthetic & took 6+ months to get full range of movement back. At the time, I couldn't raise my arm above shoulder height, & had pain even washing my hair & eating and could not put my hand behind my back! it was always aching at night. I was told by the surgeon that it may come back in 10 years. It had some twinges last year & I thought it was returning - but has settled down again. I had an ultrasound when it was 'chronic' and once again, it shows some tears.
Then just over 10 years ago, I had acromioplasty on my right shoulder as it was as bad as the left was, but was a mix of frozen shoulder, rotator cuff tear & bicep tendon tear .... so needed keyhole surgery to rectify it. It took the best part of a year to get full range of movement back. Even now, I do my exercises in the shower every morning, with hot water on the shoulder (as hot as I can stand).
take care, ladies