Freq urination on half full bladder. When I'm sat, laying down, sleeping or am still, I am unaffected. Not Uti, STD, STI, BV, diabeties. What is wrong?

Irritable bladder. Sometimes a woman's bladder will become irritable. You may have the urge to urinate even when there's not much urine there. This may be related to the bladder muscles becoming easily stimulated, or possibly interstitial cystitis. If either of these conditions is present, medications can make a big difference.
Urinary incontinence. I do not know if you have had a baby or not, but you sound like you are not keeping your urine in when standing. You need to talk to your OB/GYN. He or she will be able to check your bladder function. Try some kegel exercises.