gum ball sized lump??

I've had this gum ball sized bump on my inner upper thigh for a really long time, maybe even almost a year?? Sometimes it can be painful but other times I forget about it. It's under the skin and you can see it a little bit but you can mostly just feel it and I was wondering if anyone knew what it was?? Im sorry if it's not really despcriptive but I kind of need help 🙈 thank you!!