Only stutter during harsh letters, i.e. G, J, A, K

Only stutter during harsh letters, i.e. G, J, A, K This is especially painful because I'm learning Korean and G, J, A, K pretty much form the beginning of the majority of words I've learnt so far. I'm trying to apply easy onset here but it isn't working, you cannot go "hg" or "hk" very easily and most of the time I still stutter. Any advice? Edit: I cannot edit the sounds of the characters in any way, as pronunciation is essential to get correct in Korean. E.g., I cannot make the K sound like a "spitting" grawl, like the sound one does before spitting, even though that would help in english.