Yea i hold run then i go right, when i press jump it doesnt work but if i relase run then it works, pretty weird
Different keyboards have different key rollover limits, which is the number of keys you can press at the same time and have all the key presses still register. I suspect this is the problem you're facing.
It may change depending on which keys you are pressing, for example right+z+x could not work while left+z+x could work. Really unfun problem to have, but I believe it is mostly unfixable without changing keyboard, sorry.