Yes, probably you might be having mucocele.
But you haven't mentioned it's colour and size. Color is one of the major diagnosis criteria. There are many other conditions which shows this kind of sign and symptoms like blockage in any salivary duct, stone formation in any salivary gland, any traumatic sharp tooth edge, traumatic bite etc.
Next Steps
Go and visit any good nearest dentist to get correct diagnosis.
Health Tips
Dear, diagnosis can't be done through Google Searches. You have already wasted your much time. Any further delay might increase the problem.