Hypermobile Syndrome Support Group
Hypermobile syndrome is characterized by the ability to move a joint beyond normal range. People with hypermobility syndrome may develop other conditions caused by their lax connective tissues. These conditions include Gastroesophageal Reflux Disease (GERD), Irritable Bowel Syndrome (IBS), varicose veins, flat feet, scoliosis, sprains, tendonitis, and bursitis.
You probably have the right idea, in trying stretches and the pool. I suggest some physical therapist (physiotherapist) visits to discuss that and make sure your workout exercises are right for you. Maybe massage there would help. I think you'll make gradual progress once the correct workout is established.