travelling from Monterosso to Sorrento Italy

Kerri, it would have been best to post your question in the Italy rather than Montenegro forum.

But the short answer would be train (Trenitalia) to Napoli Centrale, and then local Circumvesuviana commuter train to Sorrento. You can explore your options to Naples here:

http://www.trenitalia.com/tcom-en

At Napoli Centrale, walk through the station to the adjoining Napoli Garibaldi station and purchase tickets for the local Circumvesuviana train, Naples- Sorrento line. Current schedules are here:

http://www.eavsrl.it/web/sites/default/files/allegati/Orario%20Napoli%20Sorrento%20con%20Pozzano%20e%20Scraio%20e%20viceversa.pdf

As with any local or regionale train (no seat assignments) don't forget to validate your tickets before boarding this one! This is also the train you'll use if planning to visit Pompeii from Sorrento (Pompei S. Villa Misteri on the schedule).

Thank you for your reply.