Your hamstrings probably aren't tight
The most misdiagnosed restriction in the gym. Before you stretch them again, check what your pelvis and nervous system are doing.
Hamstrings that feel tight every single day, no matter how much you stretch them, are usually not short. They're protecting something, or they're being pulled long from the other end. Stretching harder is the one response that reliably doesn't help.
Three things that masquerade as tight hamstrings
First: anterior pelvic tilt. If your pelvis is tipped forward, your hamstrings are already at close to full length before you even bend over. They feel tight because they are — but lengthening them further isn't the fix. Restoring pelvic position is.
Second: neural tension. If your sensation is more like a sharp, electric pull down the back of the leg rather than a broad muscular stretch, you may be tensioning the sciatic nerve rather than the muscle. Nerves respond to gentle gliding, not aggressive static stretching.
Third: protective stiffness. Hamstrings that are weak in their lengthened range will feel tight as a protective strategy. The nervous system limits range it cannot control.
The test that tells them apart
Lie on your back and raise one straight leg. Note the range. Now do the same with your lower back deliberately flattened and pelvis tucked. If the range improves noticeably, your problem is pelvic position, not hamstring length.
What actually works
Load them long instead of stretching them passively. Romanian deadlifts through a full controlled range build strength at length, which is what changes both the feeling and the injury risk. Add dead bugs and cat-camels to restore pelvic control, and open the hip flexors so the pelvis can sit back down.
Range you can't control gets defended. Strength at length is what gives it back.