as a share holder in a company, what rights do I have when it comes to my obligation?

If I understand you correctly, you maintain that one of the shareholders of a corporation has taken money which should have been distributed to all the shareholders, either because he took corporate money or he stole a corporate opportunity (i.e. he did a job, or made an investment, etc., individually which he should have done for the corporation.)  If so, the corporation can sue the individual to recover the monies.  In certain cases, for example where the offending party controls the corporation and will not agree to have the corporation sue himself, one or more of the corporation's other shareholders can bring suit in the corporation's name.