All opportunities involve risk no matter how simple. There's the risk of taking an opportunity and the risk of not taking an opportunity. Each choice has consequences no matter how simple or complex. Just because an opportunity is good does not mean the choice is simple or doesn't affect others. There is always a risk involved.
Yes, I believe that all good opportunities involve risk. In fact, I believe that everything involves risk in the end. In order to move forward in life we have to be able assess the risk, take measures to mitigate or avoid the risk, and then move forward. In reality everything will have risk associated with it in some way; just driving to work involves a level of risk that many people take on a daily basis.
Yes, I think that most of the good things that you will get a chance to do in life are going to have some sort of risk associated with them, and that you need to be willing to take on the challenge and try to make yourself a lot better.
I believe all good opportunities involve risk. I believe most people realize that opportunities aren't very helpful if they don't have some kind of award and generally you don't get a reward if something isn't very risky to begin with. Risk is required to create opportunity, otherwise everyone would take advantage of it.
While many good opportunities involve risk, many also do not. Of course, this depends on the nature of the opportunity. Things like a job opportunity invariably involve some sort of risk, but there are definitely 'sure things' out there. For instance, a CD (Certificate of Deposit) with a guaranteed payout represents an item that has no risk involved, and a guaranteed opportunity to profit.