It's not common to sue for anything really. Most people don't ever sue anyway, but a small amount of people sue a lot, backed up by the armies of attorneys that advertise on daytime tv and bill boards. My wife works in liability defense and it is common that most plaintiffs have been involved in other lawsuits. Car wrecks, slip and fall, wrongful terminations, plaintiffs will often have 2 or 3 ongoing cases. They are all generally bullshit but will settle out for between 20-40k after a year or two of depositions and back and forth.

One interesting thing though is that pain and suffering is typically calculated at 2x medical costs. So those crazy high bills work in your favor when you are suing someone.