Lyme Disease: This condition, caused by the bacterium Borrelia burgdorferi, can present with a wide range of symptoms including headache, fever, joint pain (especially in the knees), and less commonly, difficulty urinating. The "ringing ears" could be interpreted as tinnitus, which has been associated with Lyme disease in some cases. Given the combination of systemic and specific symptoms like joint pain, Lyme disease emerges as a plausible diagnosis.

Viral Infections (e.g., Influenza, Mononucleosis): These can cause fever, headache, and body aches, including sore joints. Some viral infections might also lead to urinary symptoms due to systemic inflammation or secondary bacterial infections.
Rheumatoid Arthritis (RA): While primarily known for causing joint pain and stiffness, RA can also lead to systemic symptoms like fever and might indirectly cause urinary difficulties through medication side effects or associated conditions. The "ringing ears" could be related to medications used to treat RA.
Urinary Tract Infection (UTI): Could explain the difficulty urinating and, if the infection has spread to the kidneys (pyelonephritis), might also cause fever, headache, and systemic symptoms like joint pain.

Meningitis: Although less likely given the combination of symptoms, meningitis is a medical emergency that can present with headache, fever, and stiff joints (due to systemic inflammation). The difficulty urinating could be a sign of severe illness affecting multiple systems, and tinnitus could be a less common symptom. Meningitis requires immediate medical attention.
Sepsis: A life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. Sepsis can present with a wide range of symptoms including fever, headache, joint pain, and urinary difficulties, especially if the infection is urinary in origin.
Endocarditis: An infection of the heart valves, which can cause fever, joint pain, and systemic symptoms. Although less directly related to the symptoms of ringing ears and difficulty urinating, endocarditis is a serious condition that requires prompt diagnosis and treatment.

Relapsing Fever: Caused by certain species of Borrelia, this condition can present with recurring episodes of fever, headache, and joint pain. It's less common and typically associated with exposure to ticks or lice.
Brucellosis: A zoonotic infection that can cause fever, headache, joint pain, and swelling, among other symptoms. It's rare in many parts of the world but should be considered in individuals with exposure to infected animals or their products.
Sarcoidosis: A condition characterized by the growth of granulomas in various parts of the body, which can lead to a wide range of symptoms including joint pain, fever, and less commonly, urinary difficulties. Tinnitus has been reported in some cases of sarcoidosis affecting the nervous system.