Any story has to be about conflict. Conflict is when one character wants something and another character or circumstances or both gets in their way. The story is how they overcome that, if they do at all, and what their reaction is to their success or failure. Also are the failures temporary? Have the failures been set up by opponents? If so, what happens when your hero/heroine finds out?
Overcoming obstacles is a real test of what a character is capable of/discovers what they're capable of. Obstacles are crucial to any story then. The great thing is that much as we don't like obstacles getting in our way, neither should our characters and their reactions can add depth to the tale. Obstacles can also show your characters are "real" given very few people welcome problems.
And naturally the obstacles should worsen as the tale goes on. There is great fun to be had in putting your characters through the mill so go for it! Characters have to have something to lose or to gain and it's got to be something compelling.