I found a small bump in between my chest and belly it's not visible but painful when pressure is applied, can you tell me what could it be?

Cyst, hernia. The small lump from your description could be a benign cyst, a small hernia, or other growths. It is impossible to determine without an exam what it is. There is no self treatment. It is best you see a physician for reassurance. If the exam is not enough, the doctor ma recommend an exam such as a sonogram.
Difficult to say. If it does not go away on its own, this would need to be looked at, as it could be anything from a hernia to an infection. See a doctor and be prepared to say how long it has been there, whether it changes with food or bearing down (like coughing), and whether you've had any history of surgery in this area or similar problems in the past.