Lyme Disease: Given the patient's history of hiking in areas with ticks, the migrating pain pattern, fever, chills, and swelling in feet and fingers, Lyme disease is a strong consideration. The absence of a rash does not rule out this diagnosis, as not all patients with Lyme disease develop the characteristic erythema migrans rash.

Viral Arthritis: The patient's symptoms of widespread migrating pain, fever, and chills could be indicative of a viral arthritis, such as parvovirus B19 or hepatitis B. The lack of digestive changes or recent infections does not entirely rule out this possibility.
Reactive Arthritis: Although the patient did not report recent infections, reactive arthritis (previously known as Reiter's syndrome) could still be considered, especially given the pattern of joint pain and swelling.
Fibromyalgia: While fibromyalgia typically does not present with such an acute onset, the widespread pain, worsening of symptoms at night, and improvement during the day could be suggestive of this condition. However, the presence of fever, chills, and significant swelling makes this less likely.

Septic Arthritis: Although the patient's symptoms have migrated, septic arthritis, especially in multiple joints, is a medical emergency that must be considered, particularly given the fever and significant joint swelling.
Endocarditis: The presence of fever, chills, and migrating pain could, in rare cases, suggest endocarditis, especially if the patient has a history of heart disease or intravenous drug use (not mentioned but important to consider).
Neurological Conditions (e.g., Multiple Sclerosis): While less likely given the pattern of symptoms, certain neurological conditions could present with widespread pain and should not be missed due to their significant implications for patient management and prognosis.

Relapsing Polychondritis: This rare autoimmune disorder could present with migrating joint pain and fever, among other symptoms like cartilage inflammation.
Sarcoidosis: Although more commonly associated with lung and lymph node involvement, sarcoidosis can cause joint pain and swelling, and it might be considered in the differential diagnosis of a patient with widespread migrating pain and systemic symptoms like fever and chills.
Whipple's Disease: A rare, systemic bacterial infection that can cause joint pain, fever, and a variety of other symptoms, including gastrointestinal ones (which were not present in this case, making it less likely).