I would like to know what the difference between a Rn and Lpn? Can lpn's work in a hospital?

Yes, but there is a huge difference in responsibilities between the two.

Becoming a Nurse - RN or LPN? (http://www.nursingjobshelp.com/rn_or_lpn.htm)

LPNs can work in a hospital, but most cannot give out narcotics. LPNs are the scut nurses for RNs, the LPNs do the "dirty work" for the RNs

Unfortunately, with your record, you won't be able to work in the medical field unless you get these charges exonerated.