You have quite a few lymph nodes in this area. Lymph nodes play a huge role in filtering out infection. This very well could be a lymph node or several lymph nodes together that have become inflammed. Since you just noticed it, it might not have been there long and the palpation is probably making it sore and tender. My suggestion is to try to not touch this area and give it a few more days. It should and probably will resolve on it's own. If it does not, however, or gets larger, etc...you will need to present it to your Dr and let them do an Ultrasound.
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