Hello needtoknow00,
I can not speak for every surgeon but it is common practice for surgeons to use dissolving suture, especially in sensitive areas like the vaginal cuff. However their are always exceptions, especially if grafts were placed. Unfortunately you must follow up with your surgeon for answers. If it is a suture that has been around for 4 months and causing symptoms perhaps it can be removed in the office.
Best wishes
I had a da Vinci hysterectomy also (last year). Those probably ARE stitches on your vaginal cuff. My gyn said they can take up to 6 months to dissolve.