Increase babies physical activities. Taking her for walks, introduce play gym etc. Start feeding her in regular intervals. Start with night massage.

No it shouldn't cause harm to your child.

Below are the most common reasons
1 Diaper full 1st check the diaper
2. Baby is hungry n demanding feed. Ensure that you feed the baby
3. Baby may have colic Pain you can use mamaearth roll on it works. Colicaids to be given only in emergency situations.
4. Baby is not comfortable in cradle and he wants to sleep with u. Or you can try swinging him if above three reasons are already ruled out
5. It's summers so may be baby is dehydrated ensure that you feed in regular intervals. See to it that night wear for sleep is cotton wear.
These can be the common reasons however you need to rule first three common reasons. And then probably start looking for other later. My baby use to cry in the night and use to demand for feed almost after every hour. Later post 3 months only I could get into a routine which he is now. As all mother's say sleep pattern improves post 3 months.

Meri sister ki baby b aesi he thi toh tng a k meri sister ne usse apna feed churva lia . 3,4 days boht zid kia pir bd mei theek ho gae . Din mei achy se kihlati pilati . N raat ko pir dood glass mei dia krti . N now she has a full sleep . N doesn't irritates my sister .

Is she is having the right amount of bm ? And did you started semi solid food or not? Maybe the empty stomach of ur baby will lead this kind of sleepless nights. Try to play n cuddle with her.

Feed him bfr sleep well.. feed burp n then make him sleep.. it l help ..

Due to colic .... give colic drops

Hi give nasal saline drops in both the nostrils and suck it back with nasal bulb to clear the airway and stuffed nose use humidifier in baby room to provide humidification and give steam inhalation thrice a day and lots of fluids in the diet

What was her birth weight. Don't look at the other babies and compare every baby is different. My baby also looks lean n long. Per doctors the weight to be double birth weight by 6 months.
Spitting is normal (unless it is not excess) ensure that you burp your baby after every feed. Also introduce tummy time exercise too.

Give dinner properly,
While going to bed,you jus give one glass of milk nd make her to sleep...

Nd now it's summer too,
Might she feels hot too,
Make her to dress-up in cotton wear nd feels comfort too...

Don't make her to sleep for more time in day...
Make her to play,so that she feels tired nd sleeps whole night...