I run and i think that i am running properly but who knows if someone takes a video with a good camera , may find some fault with my running(overpronation, underpronation etc). Is there any way to check or are there any experts who could help if I pay them. Are there any shoes specific to these that can help.
If you go to a decent running shop they will be able to analyse your gait and whether or not you under or over pronate. They will also be able to recommend the best shoes for you. This is usually done on a treadmill with a camera, and you won't have to pay extra for it.
Unless you are a top level or shorter distance track runner (where running style can affect speed) I wouldn't worry too much about your style, unless it is causing you to get injured.
I hope that helps
It is not only about over/underpronation. There are other subjects for running technique where actual experts can help you: if you don't step right under your vertical, if you have a leg shorter than the other (most probably everyone has, it may be significant enough or not), if you bend your feet to the interior, and so.
Injuries aren't gentlemen, they tend to appear in the last weeks of your marathon training and stay for long. If you can afford profesional advice in a sports medicine clinic go for it. If doing it saves you just one injury in all your sport life and a pair of sessions of physiotherapy, it paid both in headaches and cash. And I would not rely in the advice you can get in a shop: even if they provide some sort of advice, they may be at most "technicians" with a crash course in the most obvious things.