Son (2017) has had recurring elbow pain for the past couple of months. Started around the beginning of January. He would be able to throw an inning or so, and then the next day not able to throw at all. Take a couple of weeks off and he was able to throw again without pain - throw an inning, pain would come back the next day.
Family friend that is a physical therapist who specializes in pediatric athletes ran him through the stability tests and found no issues other than some minor tendon inflammation. Told him to not throw for a few weeks to let the inflammation clear out, do some PT and see if there was any progress. The inflammation cleared, and my son felt significantly better in the elbow - but still was having pain when throwing.
So off we went to see an ortho, and after taking x-rays he suspects a slight fracture where the ulnar tendon connects to the bone (I want to say at the medial epicondyle, but I don't have the diagnosis in front of me.) He theorizes that the fracture may have been partially healing in the down time, then re injured once my son started throwing again. From what I was shown on the x-ray, it's not a complete fracture - more of a wide crack through about half of the bone. We're having an MRI scheduled to rule out any ligament/tendon damage, but he doesn't suspect any based on his exam.
The ortho said the issue possibly can be blamed on the fact that my son gained about 30 lbs of muscle between August and January and was throwing significantly harder. In his words, he had the muscles of an adult - and the elbow of a adolescent. It just couldn't handle the stress being put upon it.
I'm keeping my fingers crossed that the MRI doesn't show any issues, but regardless it looks like he is done for the spring.