What can i do to prevent stiff neck/neck pain after lifting weights?

Modify your : Technique as well as look to change your amount of weight and reps or look to use a bench to support your upper back , neck and head or even change from free weights to machines or vice versa. It may be a good idea to due a light cardio warmup and stretching before and after while not overdoing it as well. If issues persist, see your doctor for evaluation and recommendations.