Why do I get morning headaches?

MAYBE THESE. Morning headaches can be due to uncontrolled hypertension (but must be quite high), maybe hypothyroidism, neck arthritis, jaw problems with/without bruxism, sleep disorders, and perhaps migraines. Also, consider medication reactions.
Morning headaches. You may have cluster headaches which wake you up, or tension headace, or related to muscle spasm in neck due to disturbed sleep, or due to sleep apnea, or untreated hypertension. It can also be due to TMJ syndrome. They are strongly associated with mood disorders and depression.