Cellulitis: This is a common condition characterized by skin redness, warmth, and tenderness, usually due to a bacterial infection. The symptoms of cellulitis can vary from mild to severe and can occur anywhere on the body, making it a likely diagnosis for tenderness to touch.

Muscle Strain: Overstretching or tearing of muscle fibers can lead to pain and tenderness, especially when the affected area is touched or moved.
Insect Bites or Stings: Certain insect bites or stings can cause localized tenderness, redness, and swelling.
Abscess: A collection of pus that has built up within the tissue of the body, which can be tender to the touch and may be accompanied by redness and swelling.
Phlebitis: Inflammation of a vein, which can cause pain, tenderness, and warmth along the affected vein.

Deep Vein Thrombosis (DVT): Although less common, DVT can present with tenderness, especially in the legs, and is a potentially life-threatening condition if not treated promptly.
Osteomyelitis: An infection of the bone, which can cause pain and tenderness over the affected bone, and if missed, can lead to serious complications.
Necrotizing Fasciitis: A severe infection of the tissue beneath the skin and surrounding muscles and organs, which is a medical emergency.

Ehlers-Danlos Syndrome: A group of disorders that affect connective tissues supporting the skin, bones, blood vessels, and many other organs and tissues, which can lead to easy bruising and tender skin.
Sickle Cell Crisis: A condition that occurs in people with sickle cell disease, where the abnormal sickle-shaped red blood cells can get stuck in small blood vessels, leading to episodes of pain, including tenderness.
Complex Regional Pain Syndrome (CRPS): A chronic pain condition characterized by severe, burning pain at the site of an injury, which can also include tenderness to touch.