i just got a pair of these yesterday, last night i messed around and got a good fit, listened for maybe 20 minutes at maybe 40-50% volume. a little while later i had a slight ringing in my left ear and this morning i woke up with a headache...that i still have. it felt like i had them in right and at an appropriate level. this is my first pair of in-ears so i dont know if it's just getting used to them or what. anyone else experienced this?