Go and get Arnica Gel or Traumeel (traumed gel.) Put either one on at least 4-5 times a day. Dont smother it and dont rub too hard…just gentle enough to the touch.
DONT stretch…if you stretch anything stretch your hip flexors as long as you have no pain in the hammie.
Compress from bottom up…and dont train lower back or hammies for a little…hammies can linger for awhile and throw off the rest of your pelvic structure.
I had the opposite way work for me. Whenever I did not stretch them or train them I would strain mine soon as I came back.
I found rice good for the first 2 or 3 days, then LIGHT to normal stretching and I worked mine using stiff legged deadlifts starting at a very light weight.
Theres no way of really telling why you pulled yours, if you weren’t using a weight that you never used before. But MOST hamstring pulls are from a deep fatigue. Not just one day fatigue either, like squatting heavy on monday, deadlifting heavy on wednsday and not eating enough in between type of fatigue.