M.M.
Everything is connected.
Since you didn't address the shin splints, the stress on the muscle moved into your quads. Our hip flexors cross the body, and the tight left quad connects to the right hip flexor...thus the pain you are feeling there now.
In short, address the shin splits (get to a chiropractor or massage therapist...trigger point therapy will help a lot with this quickly), and the rest will go away.
If you don't, it's going to move into your lower back and glutes.
For the shin splits, if you are not going to take time off, get an ace bandage and wrap your shin at the point of the point. It will hold the muscle to the bone, which is what is causing the pain.
My chiropractor is a bit of a naturalist and has helped me understand how pain travels and injuries/stress in one part of the body can start to affect others. This one is pretty text book, and something I deal with on my own as well. I see him every two weeks to keep me in shape, since I am also not willing to take time off.