Why cant i get cleavage?

Im 17, 5'6, and 140 lbs. I have a thick bottom and a muscular body, ive been athletic all my life. It seems me breasts point outward and their is a big space between them. I have two double push up bras from la zenza that are size 32B, the 36A i tried on looked wierd undershirts and didnt give me any cleavage the 32B fit but as soon as i have it for a day when i put my arms above my head or lie down the bra perks and i have a huge space, no bras seem to fit me and ive come to hate my breasts not cause their small but because i spend so much money on bras that dont even fit, when i got fitted th woman said i was a 36C... ha nice try..help!