I hit my head this morning. i got this knot in my chest and my breathing was funny. it went away. should i still go to the doctor?

Head injury: If the head injury did not cause loss of consciousness or persistent symptoms like nausea, vomiting, or changes in your pupils, you probably do not need to see a doctor. It is unclear how a head injury could cause a knot in your chest. When you're stunned, you tend to involuntarily hold your breath. As long as these symptoms have resolved, i would not be concerned.