27/f got up to do something had no urge to pee sat down for a min as I got up urine came out no burning or pain happens often why? Cant hold it....

Incontinence. Your symptoms are consistent with possible stress incontinence (sui) which occurs with activities such as coughing/sneezing, lifting, straining, exercising, and change in position, and is related to weakened pelvic floor muscles. Another possibility is non-urge, non-stress incontinence which is sudden uncontrolled urine loss due to involuntary bladder contraction. Urological evaluation recommended.