Hello, I need your suggestion about what saddle and shorts to buy. I cycle for quite long distances over 100 km and always feel uncomfortable on my saddle after couple of hours. By sitting on my bike that long starts to irritate the skin of my butt and nether regions. Ive got a small italian road bike. Or is it something like wrong geometry of my saddle?

Assuming that you have been professionally fitted for the bike size and geometry, then the problem is likely between you and the seat. I don't have any brand suggestions because everyone is different. What might fit another rider very well, you may find painful. People can tell you what they ride, but it may have no relevance for you.

Generally speaking, the more expensive the shorts, the better the design, workmanship and materials. I'd be wary of $50 shorts, but $300 ones probably are not necessary either. As the rider-shorts-seat interface if very personal, you will be lucky to hit it right the first time. It may require 2 or 3 iterations to find what works for you. I don't know of any shortcuts for this.

Saddles are very personal but realistically if you are riding a low quality one that came with the bike almost any higher end one will be a vast improvement. Fizik and Selle Italia may be a good place to start with and stand a high chance of you being able to get a test saddle. As far as shorts you should look at the pad you sit on as a first consideration and then find the ones with it that fit you the best. Not sure what brands you have easiest access to and could try on to assure best match with your needs. Good luck.