Shin Splints (Medial Tibial Stress Syndrome): This condition is characterized by pain in the medial calf, often due to overuse or repetitive stress on the tibia. The pain can be exacerbated by activities such as running and can be tender to the touch.

Deep Vein Thrombosis (DVT): While DVT typically presents with swelling, warmth, and discoloration of the affected limb, pain and tenderness to touch in the calf area are common symptoms. It's a plausible diagnosis given the location of pain.
Muscle Strain: A strain in the muscles of the lower leg, such as the gastrocnemius or soleus, could cause pain in the medial calf. Pain to light touch would be consistent with muscle injury.
Peripheral Neuropathy: Conditions affecting the peripheral nerves, such as diabetic neuropathy, can cause pain and hypersensitivity to touch in various areas, including the calf.

Compartment Syndrome: This is a medical emergency where increased pressure within a muscle compartment leads to inadequate blood supply to the tissues inside the compartment. Symptoms include severe pain, especially on palpation, and pain with passive stretching of the muscles within the compartment. It's crucial to diagnose early to prevent permanent damage.
Popliteal Artery Aneurysm or Thrombosis: Although less common, these vascular issues can cause calf pain and must be considered, especially if there are symptoms of limb ischemia.

Eosinophilia-Myalgia Syndrome: A rare condition associated with severe muscle pain, among other symptoms, which could potentially cause pain in the calf area.
Chronic Exertional Compartment Syndrome: A condition that causes pain, swelling, or cramping in the affected muscle compartment (often in the lower leg) during exercise, which might be considered if the pain is activity-related.
Nerve Entrapment Syndromes: Such as tarsal tunnel syndrome, which affects the posterior tibial nerve and can cause pain, numbness, and tingling in the foot and potentially the calf area.