Doctors donât know exactly what causes migraines. It appears that migraine headaches may be caused in part by changes in the level of a body chemical called serotonin. Serotonin plays many roles in the body, and it can have an effect on the blood vessels. When serotonin levels are high, blood vessels constrict (shrink).
Average Salary. The average annual salary for physical therapist in the United States is $86,520, which is 103% higher than the average income of Americans. The median pay for PTs is $7,210 per month, $1,663 per week and $41.59 per hour.
Top-paid physical therapists can make over $53 per hour. You can earn over $53.21 per hour as a physical therapist if you are among the top 10 percent in earnings, according to May 2011 data from the Bureau of Labor Statistics. But you better have the necessary compassion, attention for detail and physical stamina required of this profession.