Injuries/Trauma: A fall, blow, bruise, or injury to the muscles and ligaments (sprain) can cause increased blood flow to the area, causing swelling and pain.
Infection: Bacterial infections (such as cellulitis) can cause the area to become red and swollen and be very painful. It can feel warm to the touch.
Arthritis: Inflammation in the joints can cause pain and swelling (such as rheumatoid arthritis).
Allergy: Insect bites or contact with allergens can cause the area to swell quickly and cause pain or itching.
Poor Circulation: Venous insufficiency can cause swelling and pain.
Overuse: Continuous overuse of the same muscle or joint can cause swelling in that area.
