How can I avoid severe foot pain after work?

Peoorthist. Consider working with a certified pedorthist and /or podiatrist to ensure that your shoe/ boot choices are optimum for your foot health.
Many possibilities. Your pain could be as a result of many different things. A thorough history and physical exam and possibly some laboratory and radiology exams are needed to determine the exact cause. Causes of pain may include: trauma (fracture, sprain, arthritis), infection, metabolic conditions (gout), musculoskeletal or biomechanical abnormality and neurologic conditions (neuropathy).