What Causes Lump On Back And Shoulder?

Hi, I am an asian male 29 years old. I drink and smoke regularly. I am reaching out regarding a colorless lump on my back/shoulder which doesn t hurt. It is about a quarter inch wide lump which I believe started as a pimple. I do have minor back acne. It formed a few months ago and doesn t seem to be growing or going away. Do you have an idea of what it is? Should I seek medical attention? Thanks,