Hi !The muscle of the srotum (cremasteric muscle) which houses the testis is an involuntary muscle which contracts of its own and can draw the testis upwards. So the symptom of your testis sitting high could be due to the normal cremasteric contractions.
The other possibility is an abnormal position of the testis higher up anywhere in the inguinal canal
area starting from the lower inguinal area to the region of midpoint of inguinal ligament.
In both the cases, there could be unnoticed repeated trivial trauma to the testis leading to inflammation of the testis hurting you at that time. During this time you have to have proper scrotal support, with some anti inflammatory drugs. In case the problem disturbs your daily life, then you should consult a Urologist
. Good luck.