Inflammation?

I had a bit of a cold with a sore throat until yesterday, then yesterday it was just a runny nose, or rather a mild one with a blocked nose, then I went swimming with friends for 5-6 hours. We played football for 30 minutes. Then I had a headache etc. with slight chest pain. Now after waking up, my neck is very, very tense. Chest tightness, you could say, headaches and the typical symptoms like dizziness and, occasionally, brief loss of consciousness. As a 14-year-old, I just don't know what it is or whether I need to see a doctor.