Yes you can take both at the same time but I would recommend you to consult your Homoeopath for urticaria too then you can get permanent treatment for both conditions together without any side effects. Allopathic medicine will only give you temporary relief for urticaria.

Homoeopathic medicines can also treat your urticaria. You can consume certain allopathic medicines akong with certain homoeopathic medicines, it won't cause any harm but it might hamper the action if your homoeopathic medicine.

You can take but try and take it at different timings. (6 hrs apart should be good enough)

Yes, u can but keep some time gap between the two. Also follow this to get relief from migraine 1. Take adequate night sleep 2. Eat at regular intervals. As starvation/gas can trigger migrain 3. Avoid things that can trigger migrain. Common triggers include alcohol, caffeine or poor sleep. Inculcate good sleep practices like having a regular bedtime schedule and avoiding naps, caffeine and TV before bedtime. 4. Don't take stress- Pursue an enjoyable activity or verbalising frustration to reduce stress and improve mental health. 5. Avoid foods that you know triggers your migrain. 6. Hot packs and heating pads can relax tense muscles. Warm showers or baths may have a similar effect 7. Drink water. “Dehydration can be a big cause of headaches,” For this homeopathic treatment is very effective For more details you can consult me.

Yes

You should infirm your Homeopathy doctor regarding alkergy so that he can give you medicine for the same. You can continue both together but when in Homropathy treatment is available for allergy.

Migraine and urticaria both can be  completely cured by Homeo medicines, so please ask your physician to give for your acute state first.