I totally agree with Denise - you need to see a Rhuemy. Your regular doctor can do some preliminary testing - bloodwork and urine screens. In addition to staying out of the sun, it's important to avoid stress and sulfur-products (like the meds you would normally take when you have a kidney infection).
Getting a diagnosis can be difficult - you have to be persistent sometimes. Keep copies of all test results. Make a log of when your symptoms occur - severity, etc. Take photos of your rashes etc because they will "miraculously" disappear the day before you meet with the Rheumy. (ha ha)
There are A LOT of other diseases that may mimic the symptoms you're having - so be somewhat patient with the screening process. It's a disease that they frequently diagnose thru a process of elimination. The more astute you are about your body and symptoms, the easier you can make the process. The Arthritis Foundation and Lupus Foundation are great resources for learning more about the disease and treatments. (And, most of the info is free)
Keep us posted and let us know if we can offer any other insight.