My Doberman is limping but not whining. Is he still in pain?

Poor Brownie! Limping means he is in pain, so even though he's not whining, he would not be limping if he wasn't in pain. In the picture you provided, it looks like he's standing high on his paw, which could indicate its painful for him to put pressure fully on his paw. He could have injured his paw, or it could be that he has a foreign body in his paw. Check his paw and see if you can find an injury or a foreign body. If you do, he likely will need to see a vet to have it treated. If you can find an obvious injury or a foreign body, I recommend resting him for the next 48 hours. No running, jumping, or playing. Take him out to toilet on a leash, and bring him right back in when he's done. If he still appears painful after this time, then I would take him into the vet for an exam. The vet can diagnose where the pain is coming from, and can dictate a treatment plan for it. He may also benefit from some pain medications, which the vet can prescribe. Please do not give him any human pain medications, as many are toxic to dogs and can be fatal if given. I hope this helps!