Strange, I just found this thread right beside on of mine. Aside from my recent left pec strain, I am also rehabbing a hamstring strain. Mine is much older, but I am making progress after largely rehabbing it and having a recurrence.
One option I have tried is Active Release Technique.
it is a chiropractic technique that uses dynamic movements by the practitioner to break up knotted tissue like Brett mentioned and generally promote good healing. It is at times painful to be the patient, I have joked the Chiro stepped out of a time space machine from the Spanish Inquisition. After the session there is an actual sense of relief, but one must rest for a while all the same.
for more info. there is a postal code/zip code locator for a practitioner near you (I presume North America, but take a look)
What I did the first time I got back into it was to do full range of motion squats and regular deadlifts, one session of each per week, with 3 or 4 days recovery between. I would do a combined warmup/working sets, 6 in total, ramping up the weights each set. To begin, ULTRA light, 3 sets of 12 for the warmup, then 3 sets of 10 for the working sets after, and as I say ramp up the weights but still listen to how the muscle feels an throw in the towel if that is your discretion. So when I got the full 10 at a top weight set, move the whole progression up by 1 weight increment, and eventually go 10 reps the first 3, then 8 the last 3.
Edit: Oh, I seem to remember starting with maybe 4 sets, and then when I was comfortable with the top set, add the 5th and so on and progress like I said.
do stretch. And don't do sudden, explosive moves that tweak it.
Anti inflammatories (sp?) help with pain, but the last Medical Doctor physio I saw clarified for me that they DO NOT help healing, The thing about pain, though, is that it clues you in to whether or not you are overdoing your muscle. Maybe do the lifting session when the last dose has worn off and only go back to it if you get sensitivity later.