Sounds like a situation that seeing a practitioner would be helpful.
It’s not a new situation and is not improving.
Finding out exactly what is going on is important.
Are your shoulder and back issues resolved?
Your standing position can definitely be a contributing factor to your knee pain.
Is your knee or hip overextended.
Shoes can be an impacting factor.
Is there tightness in your quads or calves?
Do you have full rom in your knee?
What is your ankle rom like?
High Hamstring Gnar, Trigger Points, and Up Stream/Down Stream
Episode 28: Better Rowing: High Hamstrings Part 1
Episode 28: Better Rowing: High Hamstrings Part 2
Pro Episode # 36 – Voodoo Floss Series # 3: The High Hamstring
Episode 278: Tissue Flossing For Better Sliding Surfaces