I've experienced leg and hip pain on iodine. That's one of the symptoms of bromism according to the Army. A number of people have reported this.
The Gulf War Vets complained of this when they got a bromide pyridostigmine shot as a nerve gas preventive. Somebody has posted the link to the Army's report. I should have saved the link because at least once a week somebody asks about hip/knee/leg pain.
Sorry you have to go through this. You can either stop temporarily or use the salt water.