I agree with all who have said to regress, re-asses, and refer to a doctor or PT. It’s usually the victim that cries out, not the criminal, so although the pain is in the hamstring, it could be coming from a dysfunction above or below.
Once client is cleared for exercise, one thing that I’ve done with clients that has helped has been to shorten and protect their range of motion. For example, I have a client who has knee pain that limits her lunge ability. So, we squat, unloaded, and I place a bench behind her so that she can eccentrically lengthen her glutes and hams on the way down, and the bench stops her from going farther than her knee can handle without pain or misalignment. We work the “down” for one set. We work the “up” for one set. For now, that’s all her knees can take, and it’s enough of a challenge for her leg muscles that we can benefit the legs without risking the knees.
Something’s up with that hamstring – pain while walking is definitely a red flag for me. Personally, I would refer that client to a Sports Medicine Orthopedic Doc for an evaluation. In the meantime, I would be avoiding any activity or exercise that aggravated it until you get some answers – something’s not right. Good luck – I hope it’s nothing major.
I hear this a lot, as I work with issues of balancing strength and flexibility, and lots of movements to open into that part of the body. Karen is completely right that backing off and reassessing is the way to go. There is pain and there is tension from muscles that are so tight they have difficulty with normal rom. A single word can have many meanings, and helping them both to figure out what they are feeling and to communicate that, that is taking some time to have them describe what they are feeling and when is very helpful. (not just for you, but for them to develop the ability to feel it and avoid moving in ways that are problematic or unsafe)
I agree with everything Karin suggests. Massage, rolling, and daily balancing rom exercises all have their place. Doing some postural assessment to see if there is imbalance is particularly helpful. The hamstrings neither exist nor function in isolation. For example, I find that if someone has a limb length discrepancy I may open the area in question, but daily motion will keep bringing it back. In these cases, and if the discomfort began after a specific incident (i.e. if it is acute rather than chronic) I will generally suggest they connect with their medical advisor or a pt.
I would back off on all of those and re-assess. Ask when else there is discomfort. When did it start? Was there a triggering event? Assess pelvis position, range of motion. Try isolated exercises for legs and hips and see whether you can isolate compensations. Also, try foam roller exercises (and if possible use a soft roller) or stretches.
Else, it is difficult to advise without seeing the client. The main thing is not to ignore the pain and assume it will go away.
Hope this helps.