To soothe is to relieve or to bring comfort. If the pounding in your head is driving you mad, it sounds like you might need an aspirin or two to soothe your headache.
Soothing is meant to make you feel better, both physically and emotionally. Spend too many hours on the beach without sunblock? You'll need some aloe to soothe that sunburn. Had a bad breakup with a boyfriend? Soothing that broken heart might take something stronger — chocolates, a gabfest with good friends, and sappy movies are usually just what the doctor ordered.