Suffering will never just come to someone for nothing. What we sow, we reap. We can't escape that. It is here you should know the theory of karma and why karma affects you. Anything that you do for your own selfish purpose will come back to you.
Every action brings a reaction, painful or pleasurable.
Instead of going into the precise reasons and breaking our brains to figure out what the karma is, just accept it. Let me accept it. In the future I'll be more careful. We are the cause for our own suffering. This is one important truth to be understood.