Judging from your question, it seems that you have not had your heart valve surgery
yet. If you have, and are getting ready to report for a post surgical followup appointment, then the worst pain is likely behind you. If you are have not yet had your heart valve surgery, then the answer to your question depends on the type of heart valve surgery you are going to have. The classic approach to replacing the heart valves is for your chest to be opened so that the surgeon
will have access to your heart so that the valves can be replaced. In many cases, this is the best approach for heart valve replacement.
There are new methods at replacing heart valves that are available at certain institutions. These methods use small incisions in the skin to have access to the blood vessels. Valves replaced with this method do not required a major surgery. naturally, there will be less pain with the latter approach, but in a young women such as yourself, the open procedure would probably be best in the long run. While some amount of pain comes with any surgery, your medical team will do a good job at providing you with adequate pain control. I hope your operation goes well.