Saturday night when I got into bed my elbow was sore, tender to touch and move. When I woke up, it was no longer sore however it was the color of a garnet. It was a perfect circle around and including my joint . I could bend it with no problem, there was no discomfort. Today, Tuesday it s gone. What could have caused that? I did not bang it. It did not look like it was bruised it was very strange. I went to an urgent care center because I had a chest cold , they said bronchitis . They looked at my elbow and said they had no idea but if it didn t go away to see my doctor.