My Son Is 22. He Has Severe Pain In Both

My son is 22. He has severe pain in both knees and his thighs. Both legs are swollen from knees up. He is having much difficult getting up from sitting position. He has had a dry cough x 3 weeks and he is running fever almost every evening - 99 .5 to 101, relived with Ibuprofen. About 2 months ago he had a large hematoma on his left leg due to a sports injury, that seem to have resolved. He has history of asthma, he is hetero sexual, lives in a basement apartment that most likely has mold. I am a nurse myself and his symptoms scare the hell out of me.