What Causes Enlarged Lymph Nodes In Groin And Unexplained Bruises In Child?

My 6 year daughter found a lump in between her hip & groin, when I checked her I found 3 lumps. I took her to her pediatrician whom a week later gave us the diagnosis of cytomegalovirus & the lumps were just enlarged lymph nodes (they feel like hard little beans). That was in the beginning of Dec. 2010, she now has enlarged lymph nodes lining that area on both sides of body & 1 cyst on her arm as well. There have been countless blood work, abdominal ultrasounds of abdominal organs as well as ultrasound of the lymph nodes. These tests were all done in Dec. I have brought her back several times for checkups, but her pediatrician says nothing to worry about. She is a normal child for the most part, I think she gets a little more worn out than I would think she should be, she does has unexplained bruises on arms & legs (old & new), & she gets stomach pain that doesn t make since along with constipation & vary rarely vomiting. I would like to believe her pediatrician, whom I respect & adore, but I have a nagging feeling that he is missing something. Could I be wrong? Also, she had a thryoglossal duct cyst removed when she was 3.