Season the pork shoulder with salt and pepper. In the insert of a slow cooker, stir together the jalapeño, ginger, garlic, soy sauce, vinegar, and brown sugar. Nestle the pork shoulder in the liquid. Cover and cook on low for 8 hours or high for 4-5 (ours cooked really fast and was done, on high, at a little under 4 hours), until the pork is very tender, rotating once during cooking process if desired. When the pork is ready, shred the meat. Strain and reserve the sauce, skimming any fat if necessary. We ended up actually returning the shredded pork to the crockpot (on warm) with the strained sauce, and it worked to keep the meat moist for longer. I wouldn't leave it too long like this though as it would eventually dry out.