My brother had asthma as a baby but I don't think they could diagnose it until he was 2. He used to have inhalers and so on, but he did outgrow it when he was older. My son wheezes sometimes if he has a cold, but not generally. It's harder for them as babies/toddlers to realise they need to cough to clear their chests. As for walking, my friend's son didn't walk until he was 16 months. I don't think it's anything to worry about.