What Is The Treatment For Ear Infection?

Hello, My 2.5 yr old son has had pneumonia every december since he was born. This past Dec. he was treated for pneumonia with Cefdinir. He had 2 courses of Cefdinir and was on zithromax as well between dec-january. He was given albuterol and xopenex through a nebulizer regularly and I was told he may have Asthma. On his 2nd course of Cefdinir he developed a red lump on his leg. The Dr he saw about the lump on his leg said it was dermatitis. he has been itching his head for months and that was also diagnosed as dermatitis. His Pneumonia had gotten worse in the beginning of January and finally went away end of January. I noticed then a pinkish red lump on his left fore-arm. It is now March and still there. He developed bad chest congestion and vomitted in Februaury was placed on Zithromax. While on Zithromax the lump lessoned and I though it was almost gone until it came back after a week or so. He has an ear infection now and is on Zithromax again. I am concerned only because my son had many x rays during his pneumonia. Could this be cancerous? I am worried this is a signal of something more serious going on. Doctors I have seen take nothing seriously until there is a huge problem. I would like to avoid another serious health problem. I would appreciate any advice. Thank You.