Cooking help, advice on tough chuck roast...??!!?

I cooked some chuck roast at 350 for about 45 mins the last 15 covered...it came out slightly tender in some parts and rather tough in most. ...I don't want the meat to go to waste can I thow it in my pressure cooker and will it make it tender or mushy???any advice appreciated...Cooking help, advice on tough chuck roast...??!!?
Chuck roast is a cut of beef that needs to braised, or slow simmered, for a very long time. (shorter, if using a pressure cooker, although I find this cut does best in the oven or a slow cooker). It needs a long, low cooking period to break down the tissue and make it tender. Heat a tablespoon of oil in a heavy skillet, and then brown the roast well on all sides. Add to a pan, add some water, beer, or stock, some onion and garlic, a bay leaf, a pinch of rosemary and thyme. Roast in oven for about 3 hours, or in a slow cooker for 8 - you can also add some root veggies, if you like, to roast along with! This is really, really good! Enjoy!