These are my symptoms: muscles fasciculations all over my body, occasional muscle spasms in my calves, locking up of my fingers (eg when using scissors), occasional especially nocturnal slight body jerks, pins and needeles. what could be the cause?

Your symptoms are complex and it is not feasible to be accurate or precise based on the description, but would urge ruling out a neuromuscular disorder. Include testing for myositis, hyperthyroidism, and even peripheral neuropathy. Hard to say if the fasciculations are due to genetic motor neuron dysfunction. See a neurologist and get appropriate studies.

It is not feasible to provide a meaningful opinion without additional history, physical examination and may be some tests. It would be prudent to see a doctor, preferably a neurologist. Wish you good health!