I have a lump on my left testicle that is only there when erect it is soft and I can push it in and there's no pain?

Exam! Scrotal masses should be examined by a doctor, even if there is no pain or other symptoms. A scrotal mass could be cancerous or could be caused by another condition which affects testicular function & your health. I therefore suggest you get examined at a medical clinic as soon as possible. I wish you well with your health! .