About a year ago, my 6-year-old son began complaining about severe leg pain. At one point, he was limping and couldn't walk at all. Over time, it diminished. However, lately it's become a daily complaint. Around Christmas time, the pain was so severe that he vomited from not being able to take it. He hasn't gotten so bad that he was unable to walk again, but I'm concerned. I have taken him to the ER and to a few different doctors. They have done xrays and have not been able to tell me what is going on. Has anyone had a similar experience? Is there a specific specialist I could take him to?