If your car door won't open from the inside or outside, there are a few things you can try to fix the issue. First, check to see if the door is locked. If it is, unlock it and see if that helps. If not, there could be an issue with the door handle itself. Try wiggling and pulling on the handle to see if it will budge. If not, you may need to replace the door handle. Another possibility is that the latch inside the door is stuck or broken. You can try lubricating it with WD-40 or another lubricant. If that doesn't work, you may need to replace the latch. Lastly, if none of these solutions work, you may need to take your car to a mechanic for further diagnosis.