My friends are discussing their problems and I'm going to tell them that I don't have any and ruin the mood.
Aren't you worried that bragging about have a problem-free life might be viewed negatively?
No matter what, I'm going to tell them that I don't have any problems.
Your friends don't need to have you throw your good luck in their face. Bragging about yourself is not a good quality and is inconsiderate to others. Find some humility and focus on the needs of others.
I'm thinking that maybe my lack of problems will make them feel better.
I'm sure your friends don't want you to have problems, but it's wrong to brag, especially when your friends are discussing things that they are struggling with. Doing this only serves to make them feel upset, embarrassed or even ashamed about what they're going through. You should be more sensitive and supportive.