I am a healthy 50 year old 73 inches 220 athletic build and former Ironman triathlete who took a 10 year break. I recently began swimming again in a chlorine lap pool, running and biking. in the last month I have been extremely sick following a moderate run and a swim. Flu like symptoms - chills, extreme joint pain, kidney pain, severe headache. No symptoms of runny nose, rash or itching. Once resulting in a trip to the emergency room where all blood work was normal and a flu test was negative. I am sick once again with he same symptoms. What is wrong with me?