Experiencing incontinence but never had a baby. had myomectomy recently to remove fibroids but still have issues. i do light weight lifting. cause??

Many possibilities: Urinary incontinence could be due to pelvic floor weakness, medications, bladder infection, chronic illness, back injury, or from mass effect from an enlarged uterus. Stress incontinence is one type of incontinence that is caused by injury to or weakness in the pelvic floor; this is most commonly caused by child birth but a long history of weight lifting could do this as well.

Hard to know: Incontinence can be caused by an anatomical defect (stress incontinence that occurs with coughing, sneezing) and may be treated surgically or may be a nerve issue (urge incontinence/overactive bladder) which may be treated medically. Both may respond to pelvic muscle exercises and voiding on a scheduled, say every 2 hours. See a specialist if this continues to bother you.