I am 18 years old and i ve recently learned that i have a swollen thymus in addition to swollen glands in my neck that have been there since a sinus infection a year ago. I am constantly sick and very suseptible to even a little cold. The last one had me end up in the ER for a shot of pain reliever due to my body hurting so bad. What could be the cause? My doctor believes the swollen thymus and constant sickness is linked, and could possibly be an autoimmune disease!