The price is based on supply and demand so obviously the value will be always volatile and that is the reason why we should just hold our coins and do not sell it immediately.
It has always been based on the law of supply and demand but also the law of supply and demand is affected with the market trends because there are people who decides to sell due to certain reasons like sudden Government regulation, that will affect the price and force the it to go down, but if a group of people buys the coins because the price is low, then it will create a sudden demand which will help the price to go up.
That's what makes bitcoin impossible to predict--we never know why, how, or when those supply and demand forces will come. Governments can cause major moves, regulation, devaluation, news, or even billionaires trying to hide their money away. There's no guarantee that one thing will happen at any given moment, so we just have to be ready for it before it happens. Maybe tomorrow someone will decide that they need $15 billion worth of bitcoin to avoid being taxed. Or a country will have a currency crisis and people will try to protect their savings. Then the price will go up.