Can you learn to sing?

I have played guitar for almost 4 years and learning to sing/play same time.

my voice is not very good, in fact it sucks…..REALLY SUCKS.

but I love being able to express my lyrics and songs when I write them.

its hard to explain but I would love to be able to sing.

I play Metal/Rock/Blues…..I dabble in jazz but thats deep stuff man!

anways can I learn to sing or is it one of those things that you are born with ya know talent or what have you?

I am really giving up hope, as I want to go out and play and sing. Just for fun! like open mic and bands for jamming etc…..

Thanks for any advice,tips, and what not.

(I have music where I sing/play if you need to hear it…message me.)