Suitable gym wear for RA and lower back pain

hello everyone. I (28, female) was recently diagnosed with seronegative RA. My symptoms started with intense lower back pain. I used to go to the gym 3-4 days a week before I started showing symptoms. From a few weeks before my symptoms started, I’ve been struggling to wear gym leggings, which are tight at the waist and hip. Now I can’t even imagine wearing those leggings due to the pain and discomfort. I do want to start getting back to the gym again and I was wondering if anyone has any recommendations for comfortable gym wear?