There are many websites that offer exercise guides, and even include video instructions for exercises. LiveStrong.com, SparkPeople.com and DotFit.com are 3 I am aware of. To loosen a tight hamstring, you want the muscle to be warmed up by moving for at least 5 minutes: walk at a brisk pace, climb stairs, use a treadmill or elliptical machine, etc. When my hammies are tight, I like warming up with what they call hamstring curls, when you step from one foot to the other and kick your heel up to your butt with the other foot. The hamstrings can be stretched standing or sitting. DON’T lock your knees… but keep the knees soft, or even slightly bent if necessary. Hinge from your hips (not your waist) and try to touch your toes. If you are sitting, keep your foot flexed. Another way is to sit down on a chair, bend forward from the hips and rest your chest against your thighs, reach down and grab your ankles.. then lift your butt out of the chair, keeping a hold on your ankles and your chest against your thighs… and straighten your legs as much as you can. I find that yoga has been helping me strengthen and loosen my muscles simultaneously. If you are not familiar with yoga, find a beginners or ‘gentle’ yoga class. Applying heat and massage should also help bring some releif over the course of the day. If it us safe for you, ibuprofen (Advil/Motrin) can also help ease the tightness and discomfort. If this is a chronic issue, discuss it with your Doctor to see if maybe it warrants further examination and treatment. Feel better soon!