I have had 5 or 6 right ankle injuries. I'm in high school and I'm an avid tennis player. The swelling has never fully gone down since my last ankle injury, about four months ago, and I have continued to play tennis since my ankle healed. Whatshould I do?

Ligament laxity. There are various reasons for chronic ankle sprains. If you have had multiple surgeries for repair and reconstruction i would recommend a ct or MRI to rule out a tarsal coalition or a problem with the tendons and or ligaments. You could also have a supinated heel which could be corrected. I recommend seeing your foot and ankle specialist and getting a second opinion.
If you have. Chronic lateral ankle instability and have had tests to show ligament damage, you should consider surgery.
In . In an adolescent with frequent ankle sprains, you have to look for a connection between the bones in the foot, called a tarsal coalition. They do not always show up on plan x-rays, since the connection may not contain enough calcium. A ct may be helpful, or even mri. Before considering surgery for the ligaments, look for an underlying cause.
Given . Given your age and your level of activity, i would say yes, you're headed to some sort of surgery. If, at any of your previous injuries, you injured ligaments, that injury could weaken them, and make them predisposed to re-injury, thus further weakening them. Assuming nothing else is wrong, you may need to have some of the ligaments around your ankle stabilized. There are several different kinds of ankle stabilization procedures predicated on which ligament(s) need repair or reinforcement. Go to a good foot & ankle surgeon, be it orthopedic or podiatric, and get it evaluated. Meanwhile, you might benefit from wearing an air cast when you play tennis to give you some protection. If you're continually twisting your ankle (inversion), you can have what's called a "lateral flange" applied to your tennis shoes. It's a 1/4 inch piece of rubber that sorta makes a little shelf on the outside of the heel of your shoe that makes it harder to turn your foot inward, thus avoiding further injury. A decent shoe maker can put these on for you.