How bent/straight is your knee when the pedal is down at 6:00?
Seat height and fore/aft position can have a big affect on comfort, as can stem height, handlebar tilt, lots of things.
Also, regular stretching is very helpful. You can improve your flexibility by doing so. Leg stretches, especially for the hamstring, can help with back problems.
- Gray 2010 carbon WSD road bike, Rivet Independence saddle
- Red hardtail 26" aluminum mountain bike, Bontrager Evoke WSD saddle
- Royal blue 2018 aluminum gravel bike, Rivet Pearl saddle
Gone but not forgotten:
- Silver 2003 aluminum road bike
- Two awesome worn out Juliana saddles