Help!

My iphone 4 has kernel panic, it is not jail broken and yes I have tried to rest the phone it seems to show fully black screens when I use safari or apps sometimes and closes unexpectedly. I've deleted all my music videos and have only 4 photos and 1 app after i was getting Messages saying my memory is full I had over 50 songs and 200 photos also around 7 apps that I cannot re-download after deleting them and still have no memory left I cannot take photo due to this or download any apps what so ever this problem started late 2015 and has worsened over time I assume it is a hardware problem that I cannot solve why is this happening ??