I lifted some heavy shopping bags and felt a twinge
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Hello, I'm Dr. Branch,
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Since you felt this when you were lifting something heavy, I would suspect this twinge has a musculoskeletal cause, and I would suspect that you strained a groin muscle, which can sometimes feel like it is coming from the groin area as well.
Especially if you don't feel it when you are not lifting anything, I wouldn't be concerned about it. If it does begin to ache when you walk or do any other activity, I would only suggest trying to rest and taking an anti-inflammatory such as Ibuprofen for the pain.
If the pain does recur and definitely feels like it is coming from inside the vagina, then a pelvic examination would probably be appropriate to make sure something there is not anything inside the vagina or cervix that is causing the pain, but I would not expect that this is the case for you.
I hope that helps.
Please let me know if you have any questions about that and I would be glad to discuss it with you further.