Thanks for staying online.
Such swelling in foot instep of only one side, can be related with- Venous insufficiency which is a condition where the valves in the leg veins are unable to pump blood to the heart which causes blood to pool below the defective valves.
It could also be related with lymphatic obstruction which is blockage of the lymph vessels that drain fluid from body tissues and facilitate immune system cell movement through the body.
Now if it would have been any heart ,liver or renal problem leading to swelling ,it will most likely lead to swelling in both foot. So, this could not be related- heart/ kidney/ liver disease.
A thorough clinical examination and tests would be done for precise diagnosis.
Please start with your primary doctor and get it managed.
Hope this helped
If you have any further question then you can ask me.
Please leave positive rating above the chat box so I can get credit for helping you today
we only get after positive feedback.
Bonus is highly appreciated.
We are here to help you until you satisfy.