Hi, welcome to our site. I am Dr Saumya Mittal, MD. Read your query. That is a very significant question and i appreciate your problem. I will try my best to answer your query I think there is a possibility that she has been on iv fluids that had been keeping up her fluid contents of the body while in the hospital. I am assuming that ever since discharge from the hospital, she is not having enough fluids. So I would suggest that you simply make sure that she is having suffeicient volume of fluids and a good meal. A little light headedness may indeed be due to something like motion sickness. A tablet, as prescribed by your gp, may up the vertigo because there may be some sedative action. So I would also suggest that she have some healthy sleeping hours for now. Recuperating from shoulder injuries can be exhaustive I hope this helps you. Inform the reports mentioned above/if any other so I can be of help further. I have given you the answer to the maximum considering the information provided. The results of the tests could further enhance my answer to you. Please do understand that some details could be extracted from a detailed history and examination. Please feel free to ask another query. I would be glad to help you. Looking forward to your return query with the details asked so that I can help you further. (If the answer has helped you, please indicate this) Best of luck.