My legs and arms (from the shoulder down) feels very tired a lot of times. like i have been walking for a long time or i have b my legs (from the behind the knee down), arms (from the shoulder down), and my neck (on both sides feel as though it has been

Hello, : Hello, i would be more concerned about a generalized medical issue than specific musculo skeletal problems with your extremities. I noted that this was marked for orthopedic sports medicine. I would start with a comprehensive physical examination with laboratory evaluation. Depending on the those results, your physician would hopefully be able to determine the cause or recommend a specialist for further assessment.