The Board denied service connection for left and right knee joint and muscle conditions, as well as shoulder joint and muscle conditions. The evidence did not support a link between the Veteran's current disabilities and his military service.,There was no medical literature or in-service records supporting a nexus between the Veteran's current diagnoses (left and right PFS and rotator cuff tendonitis) and his service.

The Veteran's claims for service connection and increased ratings have been granted. The initial rating of 10 percent, but not higher, has been assigned for pulmonary sarcoidosis. Service connection has also been established for migraine headaches, degenerative arthritis in the left knee, right knee disorder (osteoarthritis), right ankle sprain, right shoulder rotator cuff tendonitis, bilateral flat feet, and various foot conditions.

The Board has remanded the Veteran's claims for service connection due to duty-to-assist errors and inadequate medical opinions. The issues of entitlement to TDIU are also being remanded as they are inextricably intertwined with the other claims.

The Board has granted service connection for left shoulder rotator cuff tendonitis, finding that the Veteran's current condition is related to his in-service injury. The evidence shows a present disability and service incurrence of an injury, with continuity of symptomatology post-service.

The Board has granted service connection for left ankle tibiotalar joint osteoarthritis, right ankle tibiotalar joint osteoarthritis, and right shoulder rotator cuff tendonitis. The decision is based on the Veteran's competent lay statements, his service treatment records showing bilateral ankle complaints during service in March and April 1997, and a September 2023 private opinion linking these conditions to his active duty.