Do you need to stretch ear piercings to wear a ball-closure ring?

It depends on how thick the earring is you were pierced with (and the gauge of the ball-closure ring you want to put in it).

When I got pieced back in 1993, they were still using HUGE thick studs (ugh, and now i just sHuDDER to think of mall piercings and piercing guns, and how evil and unsafe they are) -- yet my mom said they were THIN compared to what she was pierced with back in the 60s. The piercing studs I see now at mall places are way thinner than the ones I had back in 1993.

If you were pierced with the thicker type studs, you should be able to get a (16 gauge) ball-closure ring in with no problem. (14 gauge body jewelry is very common too though, and that would be too big). If you got pierced with the thinner, newer studs (closer to 18 gauge, which is how thick regular, non-piercing studs are, or they can be even thinner), then you could probably still do it but it would pinch a bit at first (it would stretch it).

You didn't specify, so I assumed that you were talking about a lobe (NOT a cartilage) piercing. If you're talking about a cartilage piercing, you should pop into a piercing place and find a nice piercer to ask for advice.