From the thorns, flower and fruit it looks like it might be in the nightshade family (Solanum spp.) but after a thorough online search I couldn't find one with matching leaves. The painful poke also fills the bill. You might check with your extension service to see what might be in your area.

To locate your county's Extension Service office, use the map at the link --

Here is a link that might be useful: locate your County's Extension Service office

It could be spurge nettle.

Your message title brought back bad memories. A month ago I was cutting saplings that were sprouting through the vinca in our front garden. I felt a thorny prickly vine jabbing into my lower leg, and reached down to dislodge the vine rather than just yanking my leg free ... And found the "vine" was a big black snake that was biting me. I dislodged the snake, screamed like a little girl, leaped out of the garden and ran into the house.

I've been bit by this plant at the beach before too, unpleasant!

Bob - ouch!

Here is a link that might be useful: Stinging / bull nettle