Weight loss or weight gain ,joint pain etc implies a status of malnutrition or in other words Nutritional defeciency, which can be corrected through a balanced diet plan and supplements if found to have defeciency .
Whey protein supplements have a very specific role to play hence need to be consumed only if your diet is not supplying sufficient protein.
Next Steps
share details of your present food consumption pattern which will help me to understand your health status better and suggest appropriate Diet plan,which requires follow up atleat for 3 to 6 months with a month's interval