Taking anti inflammatory drugs like Aspirin/Ibuprofen before your workout will actually be counterproductive for your muscle building goals. Inflammation (the pump) is needed to signal the hypertrophy (muscle building) process. By taking Ibuprofen before your workout, you will blunt that response and not get as much of a hypertrophy response from the workout that you would of otherwise.
Aspirin/Ibuprofen also carries a more liver toxic nature then most oral steroids. I am really not a fan of anti-inflammatory pain medications unless they are 100% necessary.
If you want something to increase endurance before your workout, check out cadarine. It will directly increase fat loss, endurance and recovery. It won't effect muscle gains like anti-inflammatory drugs will. It also isn't a hormone or a stimulant so there are no issues of hormone suppression, cortisol increases etc. -> http://www.evolutionary.org/cardarine/