Hello,
Thanks for your query.
Tight muscles in body with pain in neck and back is a result of muscle spasm which in itself is a protective mechanism body develops so that the back avoids abnormal posture.
For pain to go, it takes not only rest (on a comfortable bed) but also avoidance of particular positions (during work, rest or recreation).
Avoid sleeping on sides and stomach in case you do. While on work don't sit in one position for more than an hour and take frequent stretch breaks. Do not bend forward to lift things up, bend the knees and hips for that. Also discontinue any strenuous activity or exercises for some time.
Having said that, you might want to consult your orthopaedician for a detailed physical examination and appropriate investigations. It might help with few medications and
physiotherapy for a few days. Physiotherapy particularly lumbar traction for a week and back strengthening exercises after pain relief work well.
Remember that medicines usually don't play a role in long term treatment, what does is exercises. Few exercises that the therapist will teach you must be done for life time.
I do hope that you have found something helpful and I will be glad to answer any further query.
Take care