Some docs say to wait and some don't. If you had an early loss I've heard lots of people who go on to have healthy pregnancies.. I think if you have a later loss it's more important to wait a few cycles for you lining and body to all get back to normal.
But Im no expert
My cycles were all wacky for the first few months, and I had an early loss. I was crampy throughout my entire cycles, so it's hard to say if it's O pain or not.