i am 14 and the banjo string in my penis head is quite short so it hurts if pulled back too much . also my head is extremely painful when touched so it is hard to clean
When did you first pull back your foreskin - is this something quite recent or something you have been doing for in excess of 6 to 8 months or more?
So males find the head seems to be extremely sensitive - it is very unlikely that this is because of a problem issue. Therefore, it is almost always a case of getting used to the feelings and in time, the sensitivity will lessen.
In terms of your frenulum it is almost impossible to give a ‘physical measure’ of what is short and what is not. The essential is that at 14 YOA your penis is still very much developing - with the maturation process potentially continuing for the next 3 to 5 years in the main.
For most young adults the foreskin and frenulum develop strength, resilience and elasticity over time and this can only develop by exposing the head of your penis and eventually these elements will sufficiently develop.
Certainly for most young men this is not a problem issue, but, for a sizeable proportion, many young adult males will need to do stretch exercises to enable the right level of elasticity to actually develop.
My suggestion would be to leave this for at least another 2 to 3 years - as simply, you foreskin and frenulum may develop naturally, anyway …