Dreams about people who've passed are pretty common, especially when grief is still fresh or when something's triggered a memory. Your brain doesn't just stop processing loss - it keeps working through it, sometimes for years. That vivid quality you're describing, where it feels almost real, happens because grief can bring dreams into sharper focus. The emotional weight makes them stick with you differently than regular dreams. So yeah, your grandmother appearing in her kitchen could absolutely be your mind revisiting memories and working through missing her.
As for whether it "means something" - that really depends on what feels true to you. Some people find real comfort in dreams about loved ones, like it's a moment to reconnect. Others see them as their brain just sorting through memories and emotions. There's no scientific proof that deceased people visit us in dreams, but that doesn't make the experience less meaningful or real to you. The fact that it moved you enough to wake up crying tells you something important about how much she mattered, and honestly, that's what matters most. A lot of people treasure dreams like this as a way to feel close to someone again.
If these dreams are happening regularly and making it hard to move forward, that might be worth talking through with someone. But having one vivid dream three years later? That's just grief doing what it does - popping up when you least expect it, reminding you of what you had.