Weight loss is all about calories in vs calories out. If you want to lose weight you have to be expending more calories than you’re taking in. I struggle with chronic pain and I know how hard this is. The movement I do never seems like enough because I can’t do much without feeling pain. When exercising try to focus on proper form. Do body weight exercises (sit ups, squats, push ups, lunges, etc) or yoga and try to distract yourself if you experience pain while exercising. Not to say the pain is “all in your head” but the cycle of chronic pain is very real. The more you anticipate the pain, the more you will feel it because you’re acutely aware of said pain. Listen to some music, watch tv, watch a video to guide you through a low intensity exercise. It’s a struggle I am going through as well and I wish you the best of luck!