Is there a way to treat/ease pain from endometriosis that does not require surgery or birth control?

Yes. Decreasing caffeine, accupuncture, botanicals and foods that cleanse the liver to help eliminate estrogen better. Also there are anti-inflammatory herbs and anti spasmotic herbs that can help.Consuming onions / garlic / leeks which contain sulfur can help. Diet low in animal protein. Foods that are high in fiber. Increasing vegetables that have indole-3-carbinol anc certain vitamin supplements.
Diet & NSAIDS. Besides having surgery to excise or destroy endometrial implants and using hormonal therapy (bcp, depoprovera or depolupron), modifying your diet to a more vegetarian diet with lots of soy protein, regular exercise and taking anti-inflammatory medication may be helpful.