In between my elbow and muscle is a lump that is sort of popping out and it aches feels like it's on a vein or something i can feel it i know it's there it's noticeable i don't know what to do this bump just showed up and only grew since then?

It is not feasible to provide a meaningful opinion without additional history, physical examination and may be some tests. If the "lump" is growing in size, it would be prudent to see a doctor. Wish you good health!

Hard to know exactly what this is based on your description only. Potentially could be a vein or maybe a cyst. In any case you will need to have this further evaluated to determine exactly what it is.