Do doctors see a lot of patients with rhabdomyolysis?

No. Most office based physicians rarely see serious rhabdomyolisis. A small number of patients on certain prescription medications will develop muscle aches and can be diagnosed and readily treated. Serious rhabdomyolisis, typically caused by severe muscle injury, hyperthermia or other serious illnesses are uncommon, but are almost always seen in emergency rooms.
No. I agree with the other clinicians regarding this question. I work solely in a hospital setting so occasionally we will see cases that result from trauma (car accident, crush injury, etc.) to large muscle groups but it's not a frequent occurence in outpatient practice. The popularity of intense exercise regimens like crossfit have increased the frequency of non-severe presentations to the hospital.
Depends. The depends on many factors including the severity of the rhabdomyolysis, kidney function, the cause of the rhabdomyolysis and if it is ongoing. The best way to treat rhabdomyolysis is to stop the causative factor and to keep yourself hydrated. (of course if the rhabdomyolysis is moderate or severe you may need to be hospitalized and to be given intravenous hydration).