How to get musty smell out of clothes and keep them out and keep it from happening to new clothes?

I'm 17, when i was younger like around 10 or younger i use to have a body odor from not cleaning myself properly and putting stuff under my arms. Well around 11 I started taking care of that problem but still had problems with finding the right deordarant,so finally i found it and it keeps me from being musty, but like my shirts would always be musty even if my arms werent,i'm guessing from sweating?I dont know.But like i started spraying stain sprays like shout and oxi-clean under the arms of my shirts to help bring down the musty smell,it worked for a while, but it wasnt getting rid of it,it was just covering it up pretty gd. Well now its like even though i spray stuff under my shirts, sometimes the smell starts coming out if i start sweating and i hate that, are there any products that are proven to help get rid of the smell or bring it down?Or is it that i might need to look into a new deoderant. My clothes smell fine after i wash them,but after i stick em on, it starts stinking. I'm getting a new wardrobe and i dont want to deal with this same problem. Any advice would be appreciated.