You need to see a doctor
about this issue if you have not done so already. It is not normal for a 20 year old person to have significant joint pain, and the issue needs to be investigated immediately to help determine whether or not you have a serious medical problem that needs treatment.
Your primary care doctor
will be a good place to start. They will be able to examine your feet, ankles, and knees looking for any overt evidence of joint swelling or inflammation. They can also examine your feet to see what the anatomy of your arches is like. Make sure to tell your doctor what makes the pain worse (such as exercise), whether the pain moves around, or whether you have seen any swollen joints at any point.
Your doctor will consider several possible cause of your pain. These include foot problems like plantar fasciitis and flat arches. They will also consider different types of arthritis
, especially rheumatoid arthritis which is the main serious type of arthritis which can occur in young people. If there is any evidence of joint swelling, they will probably want to get some basic blood tests to investigate this further.