What do I do about having migraines & the left side of the head hurting a lot more than it usually does?

Migraines. Chronic migraines are a problem for which you should be seeing your doc on a regular basis. Having headache pain that's worse than usual could be just an especially bad migraine or it could be something else. You need to get checked out right away.
Identify triggers. There are certain foods and aspects of lifestyle that can trigger or worsen headaches and migraines. The best way to identify triggers is to maintain a headache diary and keep a list of foods eaten before your migraine. Common triggers include chocolate, caffeine, cheese, msg, processed meats, alcohol, smoking/being around smoke, stress, skipping meals, lack of sleep or too much sleep.