What Could Tachycardia, Pain In Chest And Dizziness In A Teenager Indicate?

My 17 year old son had tachycardia last night around midnight. He had taken a cold mediacation loratadine and ambroxol. Also he did some weight lifting near midnight which he never does, he usually does that in the afternoon. He said that at school they gave him a pain pill, green, for a sore foot.

He said after the pisode he felt a little pain in the upper left chest area. Also he was dizzy and thought he saw some lights.