For long term, it's really suitable because over a period of few days, stocks may show a down-up-down trend but over the period of years, it is usually an upward trend. So is the case in Pakistan. The Pakistan Stock Exchange is one of the best performing markets in Asia right now. Having said that, gone are the days when you had to do all the math and economic research before investing in markets. Best option is to go for an equity mutual fund (Al Meezan, NAFA, UBL) and put your money there. These funds are handled by qualified investment managers and they invest your money only in sectors which they think are performing better than others. They are different from stock brokers who usually don't have any ethics and make money even when you're losing. On the contrary, mutual funds do their best to invest your money in Profitable stocks because it ultimately gets them profit and more investment.
So yes, investing in stocks is a good idea for next 5-10 years. Investing yourself, not so good. You should invest through mutual funds.