Hi! I have gone through your question and i understand your concern .
I would say according to what you describe , te swallen leg and ankles may be cause of standing for a long time since you dont have any cardiac dissease ,
kidney dissease ,
thyroid or
Arthritis .
Is typically after standing for a long time and when they get better during the night .This is caused of build up fluid (your blood vessels overract and you blood is more concentrated )in your leg while you stand up , and when you lay down the fluid try to gets back to normal.
I would reccomend to reduce salt in your diet ,
When you lie down elevate your feet above your heart level for 30 minute ,
Use compression stockings while you stand up,
Try to take a small break dont stay all the time in your feet ,
If you are
overweight -loose weight .
You can keep taking the multivitamis meanwhile,willl help.
If you have any of these symptoms :
Problem breathing ,
chest pain , reddnes or burning of your legs ,painful ,blisters , feve, Call your local doctor
Wish you good health
If you have any other questions please feel free to ask me .