I would recommend going to see your primary care doctor
about this issue . In some cases, it may be necessary to perform a special test, called a nerve conduction study, to make the diagnosis.
It does sound like your symptoms are most likely related to a nerve problem since the numbness and tingling
quality to the pain fits with nerve involvement. Also, the fact that the symptoms started out worse in the pinky and ring finger, and the fact that you can elicit symptoms when you press on the inner aspect of the elbow all point towards the ulnar nerve as the most likely culprit. When the ulnar nerve becomes pinched, this can lead to cubital tunnel syndrome, as you have correctly noted.
Mild cases of cubital tunnel syndrome or ulnar nerve compression can often be treated by avoiding behaviors that put pressure on the nerve (such as leaning on your elbows) and by taking anti-inflammatory medications. However, more severe cases may require surgery
to relieve the pressure on the nerve.
Book an appointment with your doctor about this issue as soon as you can to have things investigated.