I think there are a few measures you can take which may help you in your job.
First is that you should try and not stand for long periods continuously. Instead you should try and limit yourself for few hours and sit in between for half an hour.
Secondly, you should do some exercises while you are coming back to work from break in between work. These may include, twisting and turning your leg and foot in rotatory movements and massaging them a bit.
Thirdly, once you reach back home, and even at work if possible, try and raise your leg above the ground level, and if possible, above the level of your heart. This will decrease the pressure on your heart and leg muscles, and would rework the blood back to the system instead of the legs.
There are many pain killers available. However, if they do not work for you, it is perhaps time to visit your doctor and explain to him the problem you have. Doctors get such symptoms day in and out and would consider you on your requirement and will not necessarily think of you as an addict.
Hope this helped. let me know if you may need any more information