Total body weight training. Shoulders, neck, upper back, lower back, abs, triceps, biceps, chest, quads, hamstrings, flexors, calves, ....everything. Compound muscle group exercises such as squats, Roman dead lifts, and so on. Do this as a lifestyle choice , not as an occasional thing and if done right you will notice little aches and pains you've had for years go away. Be careful to avoid injury. Start light. Your neck and back problems will improve unless your back is too injured to work out.

Add to this pilates, yoga, or just stretching. It will get better.