Swelling along labia minor, one side, red, pain w/ pressure, not itchy, 1 sex partner, condom use, can only slightly feel anyth when walking?

Vaginal pain: One sided pain around the labia minor can be caused by an infected Bartholin's gland (abscess). This can be caused by bacteria accumulating in vaginal secretions which block the duct which empties the Bartholin's gland and cause an abscess to develop. See your healthcare provider for an exam. These kinds of "cysts" can be treated often by a minor office procedure.

Allergic reaction?: Possible allergy to the rubber (latex or syntheitic) condom material or to tge lubricant or spermicide. You could try a different brand of condom, made with a different material and see if you have the same response. This also could be soft tissue contusion during sex. Does not sound like infection since no discharge and no itch. See your doctor if the swelling persist.