Off and on hamstring pain for a year. this is the 6th "flare" with a bruise on my upper thigh. the pain is in the middle/bottom. strain or worse?

Investigation needed: It sounds like you may have a partially torn tendon which keeps giving you grief. See a physiotherapist or doctor who can arrange an Ultrasound scan of your thigh to determine the cause of pain. If the bruising is spontaneous then there may be further concerns of a bleeding into the muscle tissue and you may need blood tests to rule out a bleeding / clotting disorder

Unusual: That is a little unusual. First may want to verify diagnosis. Consider MRI of the hip to include muscles in that area, but also an MRI of lumbar spine to make sure this is not some form radicular pain from the back