After almost twenty years of accumulated experience following and assisting runners of every type and level, I can tell you which is the most common pain that occurs in the first weeks of training. Ready? It’s tibial soreness, commonly known as “shin splints." It doesn’t just magically appear. It’s simply what happens when, after who knows how long, you really start using your feet (sometimes for the first time) to move. The human body has a simple (and complicated) design: in order to push with your foot you need put in action your musculoskeletal system, including the tibial muscles. In the first week of training it’s absolutely normal. It’ll continue to be a “normal” pain when you run on rough terrain, change shoes or increase your speed. Anybody who practices a sport knows that these little annoyances are part of normal adaptation to the training load. But anyone that’s been sedentary for awhile has a harder time recognising the difference between simple muscle soreness and a real injury.
In mistaking pain for injury the inexperienced runner stops training until the “pain” subsides. Unfortunately when they start running again they have to often have to go back to square one and thus begins and endless cycle. Muscle fatigue is useful and let’s us know that the training was effective.
There are three important signs to be observed:

1. The pain should be bilateral. If your quadriceps, shins, calves, hurt on both the right and left side of your body...everything should be fine.

2. The pain remains the same and does not increase as you run. The day after your workout might might feel like a tractor passed over your body. Take a deep breath and wait it out. As long as the pain decreases and eventually subsides and disappears you should be fine. Or until the next workout!

3. The pain is reabsorbed. You need to develop a sensitivity in feeling that muscle tension is decreasing, even a bit. A hot bath with salts and a massage with arnica oil on the sore muscles will help speed up the healing process. Full steam ahed to the next workout!