Why do I get so aggravated and grumpy when I take my pain meds? I am going to be on opiates for chronic pain forever. Is there anything I can do?

Not uncommon. Many people on opioids complain of being grumpy. This is more due to the pain than to the medication. You may find that by taking long acting (sustained reiease) medication that your pain is better controlled with fewer highs and lows.
Chronic opiod Rx bad. For most people opoid therapy is fraught with issues:\dependency, lethargy, personality changes, low testosterone (hypogondism) in males. There are many alternatives, including gabapentin, lyrica, savella, (milnacipran) and cymbalta. These last three are pricey. And your pain mechanism should be known. I believe eveery one should try a good NSAID at full strength. There are patients who need opiod rx, but few!