Shin splints can mean any pain around the front, inside, outside portion of the lower leg.
Tendinitis of the lower leg can occur from overstress or excess pronation. The pain will normally be felt along the inside of your shin bone, but may occur on the front or outside portions.
Inflammation of the bone covering or periosteum (the material that covers your bones) can also lead to shin pain. There is too much shock or jarring, and the bone becomes inflamed, generally along the inside of the shin bone.
Stress fractures can occur in the leg or the foot. Normally, the fracture will appear low on the fibula, where the bone is thinnest.
Nerve irritation can also occur. The tibial nerve runs down the inside of the leg and around the inside of your ankle. It can become inflamed on the lower portion of the leg if it gets caught between muscles or veins that have become enlarged.
Compartment syndrome also sometimes happens. The muscles, tendons, nerves, veins, arteries, and bones of the leg run through four different compartments. Each is tightly wrapped with a cellophane type fascia. When fluid builds up in the compartment or muscles enlarge too quickly, pressure builds up there that can diminish blood flow and cause pain.