Lipomas can usually be identified on exam, but to be sure take it out, unless it is very large, it is unlikely you would be put to sleep
to remove it.
It can usually be done with local anesthesia, or a block to the arm, while you stay awake. You should not feel pain, but only pressure during the procedure. It will be sore afterwards as would be expected. But it should go away in 2-3 days.