Worker's Compensation claims cover any injury that occurs at work. In Missouri, your company is required to provide healthcare to you for your injuries. However, they get to choose your doctors, and their doctors say when you are "better". Often times their doctor says you are "better" when you are not.
Read the Missouri Workers Compensation Law and see if you can make heads or tails of it. Or, hire an attorney who knows the law and will fight to get you what you deserve for your injuries.