Unfortunately, at some point during most runners lives they will get some sort of ailment which will slow down their training- if not stop it all together for a period of time. The most important thing to realize is if you listen to your body it will give you early warning signs that something is not right. In general it is important to stop running and rest your body if-
1- You have pain for longer than 7 days
2- As you run it gets more uncomfortable
3- There is obvious swelling to the sore area
4- It effects your natural running form
Initial treatment to your injured area is RICE
Rest...stop running! Take a few days off (at least 2-3) and re-assess.
Ice....your sore area. Ice is the most natural anti-inflammatory around, and is easy to use on specific areas of the body. Ice massage is the preferred method. Take a paper cup and freeze water in it. Tear off the top and roll the tip of the ice cup over the injured area for 10-15 minutes. Do this at least 1x a day, preferably 3x a day.
Compress...the injury if there is swelling. Wrap the area tight enough for support, but not so tight it will cut off blood flow.
Elevate...the injured area. Try to keep your injured area off the floor, and ideally higher than your heart. This helps with circulation of blood flow and helps to minimize swelling.
When an injury occurs, and the above self treatment does not provide complete relief, it is important that you get medical advice from a trained medical professional. Ideally, find a doctor who treats many of the runners in your area (ask the employees in Fleet Feet Sports for recommendations.) There are two types of doctor's deal with many of running related injuries:
Podiatrists treat ailments of the foot. They may also have experience with lower leg or knee injuries if they relate to the foot.
Orthopedists specialize in bones and muscles of the body. Often Orthopedists have a specialty practice in Sports Medicine.
Following the rules above should help you to get back on the road sooner than later if an injury should happen to you. Good Luck and happy training!