If the weakness is just concerned with upper limb, associated with headache and vertigo then you need to look into cervical situation. But if it is involving both upper limb and lower limb weakness of same side, then you should check for any facial deviation or watering of single eye. If present then you have to look for brain related situation.
Next Steps
You should meet a orthopedic surgeon.
Health Tips
Be careful and observant about your symptoms.