It is important to lift with a straight back and bent knees. If you have back pain, rest your back by lying on a firm mattress or sit upright, trying to become as comfortable as possible. Regular aspirin, paracetamol or ibuprofen will often be required. Gentle heat (a hot water bottle) will also help. In some cases, back pain can take some time to resolve.
If you feel that your symptoms are worsening or not improving, consult a doctor. Osteopaths, chiropractors and physiotherapists can be very helpful in speeding recovery from back and neck problems.