Where can get pinpoint lighting for a painting?

I'm not sure what you mean by pinpoint lighting. If you mean how do you light a painting, there are two types that I know of. the simplest is to purchase a pin-up lamp made specifically for lighting a painting. It hangs above the picture and has a cord to plug into the wall or may be battery operated. Google painting lighting. Or you can have one or two recessed lights or track lights installed about 3 feet from the wall and direct them towards the painting. There are recessed lights that can be directed towards the wall rather than straight down.

There are also battery operated painting lights if you are unable to run electrical to that area.

https://www.amazon.com/Rite-Lite-LPL601XLGRC-battery-operated/dp/B005G5CETE/ref=asc_df_B005G5CETE/?tag=hyprod-20&linkCode=df0&hvadid=198066815951&hvpos=1o3&hvnetw=g&hvrand=16535291799164262011&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9017073&hvtargid=pla-349043989164&psc=1

You mean the tiny LED fairy lights? Craft and hobby stores, various on line retailers and, of course, Amazon.

https://www.amazon.com/GardenDecor-Decorative-Battery-Powered-Bedroom/dp/B071CFJ52T/ref=asc_df_B071CFJ52T/?tag=hyprod-20&linkCode=df0&hvadid=198081434346&hvpos=1o3&hvnetw=g&hvrand=8903611772995578837&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9031180&hvtargid=pla-353618347572&psc=1