Can’t get stronger arms (Help!)

I’m a high school softball player and as you can imagine having a strong arm is important for like throwing and hitting and such.

I don’t know if background helps but here ya go; I’m like 5’4” ish and naturally pretty lean, I weigh about 120ibs. I’m a good runner and my legs and core are in shape but I just can’t get my arms for some reason. I’ve been working hard for about 2 years now and little improvement has come. I have a little muscle but like I’m definitely not where I should probably be. (Its very hard to fully do 10 push ups)

Maybe I’m just dumb and I should simply just be doing push-ups everyday but I want some advice.

How can I build up muscle in my arms (preferably quickly)? And is there actually a reason why it’s so hard to build muscle there or is it simply just a you have to work at it kinda thing?

(Any advice is greatly appreciated 🙂)