Oh Erin! I would definitely tell both drs. about the MRI from 5 years ago. I hope today's MRI goes well.
More and more drs. now a day are opting for conservative treatment before jumping in to surgery (unless, of course, they feel surgery is the only way). I hope that in your case PT is all you need. As for the 93 degree pool, no way would I get in it. It would take me at least all day to recup. I do get what you are saying about swimming through. I love to swim. Anyhow, when I do PT, they will not let me in the pool and it's kept a 82 degrees.
Keep us posted on what happens.