I am young, but now my leg hurts, especially in rainy days.

Could be rheumatoid arthritis. First of all, you should take good care of it. Summer is coming, keep your legs warm. Don't blow the fan directly. If you turn on the air conditioner, you must wrap your legs, or wear pants, and eat less food with high sugar content, which is more likely to cause leg pain. Don't live in a cold and humid environment, which will aggravate your illness.

Regarding treatment, you can take care of yourself, or go to cupping, go to the hospital or physical therapy shop for physical therapy, and there are almost no side effects; It can also be conditioned with traditional Chinese medicine.