Hi and welcome,
I would think the newer symptoms are more likely to be related to a urinary tract infection (UTI) due to the higher risk of UTI's with an indwelling catheter but it could also be related to migraine, although neither would explain why your experiencing bladder retention in the first place...
"Urinary retention can be attributed to two causes, obstruction or non-obstruction:
Obstructive urinary retention causes include:
Enlarged prostate (BPH) in men
Certain tumours and cancers
Urethral stricture
Cystocele or rectocele,
Constipation
Kidney or bladder stones
Common causes of non-obstructive urinary retention are:
Stroke
Vaginal childbirth
Pelvic injury or trauma
Nerve disease in both men and women
Impaired muscle or nerve function due to medication or anaesthesia
Accidents that injure the brain or spinal cord"
https://www.depend.com.au/urinary-incontinence/causes/urinary-retention/
What's not on the above list are medication side effects eg tricyclic antidepressants, mental health conditions and menopause, the below list of causes gives more details into the different types of situations that can cause bladder retention....
"Urinary tract infection
Vaginal infection
Post menopausal changes of the vagina, genital and urinary tract
Severe pelvic organ prolapse, especially of the bladder (cystocoele) and uterus (womb) causing kinking of the urine pipe
Complication of surgery for stress incontinence of urine or pelvic organ prolapse
After a prolonged labour, especially with epidural for pain relief, difficult vaginal or instrumental delivery with episiotomy (cut) or tears, piles and pain
End of first trimester of pregnancy (12-13 weeks) with a retroverted uterus (womb that is tilted backwards) causing the cervix (mouth of the womb) to push forwards onto the urethra (urine pipe) or bladder neck obstructing it
Uterine fibroid/s situated in the back wall of the womb causing the same effect as just mentioned above
Side effects of medications
Constipation
Bladder disorders due to neurological disease or chronic over-distension may also cause voiding difficulty.
Women with psychological impairment due to anxiety and depression may likewise present with these urinary problems. "http://www.nuhgynae.com.sg/cos/o.x?c=/wbn/pagetree&func=view&rid=1069099
I would expect your urologist to have ruled out most or all common causes and diagnose you with Neurogenic bladder dysfunction (flaccid or spastic) caused by neurologic damage for a neurological condition like MS to be on your potential causation list. Urinary retention due to neurologic damage can be either the central nervous system or the peripheral nervous system, MS is just one of many potential explanations but it wouldn't be the most common so i would recommend you try to keep an open mind and not get overly worried about conditions like MS at this stage, it genuinely may have nothing to do with MS...
If you have only spoken to a dr over the phone have not sought medical further medical advice or had any tests eg for an infection etc yet, it would probably be a very good idea to see your GP or Urologist to get those tests done, i would also recommend you find out if you have been diagnosed with neurogenic bladder dysfunction and whether you require neurological consult and further testing to identify causation.
I hope that helps......JJ