I get lightheaded and disoriented during exercise especially playing basketball. cardio doctor says my heart is okay. should i see an ent or neuro?

Second opinion: Have you had a holter monitor or stress test (or both) and am echocardiogram?. You may have something serious and should get it thoroughly evaluated. If you've not had those two tests - get them. If your cardiologist won't do them, see another cardiologist.

Lightheaded: I would have you see a neurologist but also a sport's physician.