Jen, I had a completely torn rotator cuff (lifting weights) and ended up needing surgery to repair it. My most important piece of advice for you is to demand an MRI. There isn't any way to diagnose what's wrong with your shoulder without an MRI - otherwise it's just a guess based on range of motion or Xrays etc.
And if you do have a complete tear and need surgery, delay can make the fix impossible (the tendon shrivels and atrophies into the muscle and can't be reattached). In other words, watchful waiting may NOT be your best bet.
I'm not an expert on partial tears so can't help you out there, but I know that there is less invasive surgery to fix them or sometimes physical therapy works.
I'm sorry this is so abbreviated but I have to dash out the door for an appointment. I'm available to answer any questions or to help you out any way that I can.