Good evening ,I will start by sharing I have copd hypoxia and on ox 24/7 .upon exertion or laying down my heart races oxygen drops ,before I was put on oxygen I would periodically hear music ,radio,people talking usually with or followed by headache,this has increased ,I get real weak in the legs and lately seeing things like flashing light or colors changing.im concerned because I get same headache starts in right occipital bone area dr tried injections for pain in that region which has a tendency to feel quite large,my husband had brain cancer,could this I describe be related to my low oxygen levels or something else.thank you for your time.