Methylprednisolone in my opinion is a miracle drug for runners. Something hurts? Take this and the pain goes away; while the pain is gone, run your heart out. The downfall is you didn't resolve the issue which caused the pain. Let's back up and do some disclaimers.
I'm not a medical professional by any means and I suggest you read my entire post before thinking you can break a leg and go out and run. Methylprednisolone is an adrenocortical steroids. It is a heavy duty anti-inflammatory drug that unlike anabolic steroids, where your voice gets higher and your balls shrink, the inflammation shrinks instead. The decrease in inflammation decreases the pain, which can help get you to a starting line or through a race. The effects of the adrenocortical steroid is temporary and while the area of pain feels good for 2 weeks, the reason the pain occurred in the first place is probably still there.
Any drug is not without it's side effects. One side effect that isn't listed on the box, If you run on an injury, even though it's not hurting, you could be causing more damage to the tissue. So although you run for a couple weeks, you may me taking a couple months off afterwards. Other side effects if the drug is taken for a long time and/or depending on dosage include weight loss(like that's a bad thing?), glaucoma,osteoporosis and pshychosis (like I don't feel crazy enough already).
The drug is taken in a decreasing dosage to avoid Addisonian crisis, which can be fatal. When you start taking the medicine you take 6 at prescribed times throughout the day. 5 the next day, 4 the following, and so on. Just flat out stopping the drug in the middle could cause adrenal disfunctions which leads to nasty things like vomiting, direahea, convulsions and other things you want to avoid so take the medicine (as true with all medicines) as prescribed.
I have taken this successfully in the past but don't call up my doctor and ask for a prescription anytime it hurts. It takes a couple days before there is relief and the effects will last about a week after. I have never taken a cortisone shot before but would probably opt for methylprednisolone before getting a cortisone shot, as I've heard those are also temporary. The use of methylprednisolone is an option to discuss with your doctor and may help you get to the start line.