Thanks for the info- sounds like you have given yourself a nice contusion in the muscle- there are a few concerns with this type of injury.
If it happened about a month ago the tissue should be well on its way to healing- but then you raced again after that right?
Tissue healing (if you don't reaggravate) it is about 4-6 weeks.
At this time you want to keep the tissue ( muscle) mobile with out further aggravating it.
Some very light self massage can help- if it too tender on the lump just work around it. I like to use this http://www.thestick.com/. Some of my patients just use a rolling pin though!
Sometimes with a very big contusion the bruise can go right to the bone and then the bone thinks it needs to try and heal so your body starts to produce calicum deposits in the muscle. This is called myositis ossificans.
Aggressive stretching and massage can make this problem worse- the best thing to do is very light gentle range of motion -
1) lying on your back slide your heel to your bum
2) lying on your stomach bend your knee until you feel a gentle stretch in your thigh- then lower it slowly.
The trick is to keep you muscle working gently and not overdoing it.
PT will help- so keep that apt- they may need to use some modalities to help break up the scar tissue around the injury- other more aggressive stretching and massage can help too if there is no indication of myositis ossificans.
If the lump is very soft and mobile it is likely just scar tissue- if it is very hard or still hot and red then please be gentle with the stretches!

hope that helps