Started citalopram (celexa) 6 days ago. last night started having all over body itching, but no rash present. is this a possible side effect?

Not definite: The generalized itching may be a side effect but without a rash, a true allergic reaction is not certain. You could try stopping celexa (citalopram) if your physician agrees, and when itching subsides,try it again to see if the itching returns. However, your physician who knows you best should sanction this and advise you; therefore discuss this symptom with him/her.