Will 3t mri be more effective in finding cartilage inflammation in chest and neck, or am i fine with 1.5 t? any considerable differences? any safety concerns between 1.5 t and 3t?

Both: Both are fine. The 3t is a stronger magnet and does produce more high resolution images with greater detail, but a 1.5t magnet is usually perfectly capable of producing good images for such studies. Some patients have reported strage sensations or even hallucinations in 3t magnets, but this is very rare.

3T: For cartilage abnormalities, 3t imaging is great due to it's resolution capabilities, but still the imaging is dependent on the protocols set on each machine. I would trust the radiologist recommendation for which machine to use for your ailment.