Hi bruces and welcome to this forum .....
So sorry you are having headache issues from loud noise. It sounds like you may have a degree of hyperacusis (abnormal sensitivity to normal sound) in your remaining good hearing ear.
I am not a doctor, but I do have hyperacusis. I also play the piano and sing. It has been a somewhat frustrating experience in my journey with hearing loss, AN surgery with partial hearing saved, regrowth, second AN surgery with total hearing loss. The best thing for me has been getting a bone-anchored hearing device (I have an Oticon Medical Ponto Pro). My audiologist has programmed a music setting for me that essentially opens all frequency levels and that really moderates the discrepancy of sound input between the two sides of my head. In certain situations (like movie theatres and loud brass music) I have a custom-made musicians' ear plug for my hearing ear that blocks the shrill high frequencies, that also helps.
I still startle very easily if there is a sudden loud noise, that was unexpected and it sometimes creates a headache for me, but it does not last very long if the noise stops.
Send me a private message if you think it would be helpful to talk.
Let us know how you are doing.
Clarice