I get them daily, The cracking from the shoulder blades is a very tight levatore scapula and rhomboid minor, Dry needling these muscles is the only thing that i have found helps that. It also a sign that there is signs of instability in those areas. Are your shoulder blades unstable? Are the upper traps over active and the lower traps weak and streched?

The cracking from the neck would also suggest a misalignment issues? Have you had xrays that show a lack in the natural cervical lordosis?