Should I be concerned? If so, what type of doctor should I see?

I am a 58 y/o female, with painful, aching lower pelvic pain. No burning or itching when voiding, however, it's hard to get the flow started. This pain does not feel like previous bladder infections I've occasional had in the past. The pain becomes worse as the day goes on, hurts to walk, sit or lay down. Only improves with sleep, but once I'm up it begins to hurt again.

I am post menopausal, post complete Hysterectomy, and post stage 2 ductal breast cancer estrogen position (2 years ago) currently taking chemo pill with low side effects, for 3 more years.

Thank you.