I have collected together from many sources a reported list of possible symptoms that are related to one or another ACM or SM.
From personal experience I have thought back over many years after looking atthe list and thought to myself "ahhhh I have always had that, but thought it was normal" I did not obviously think it to be something related to such an awful thing like Chiari or SM.

Don't get too involved in the symptoms though and scare yourself half to death by jumping to conclusions if you see something familiar in quite a few of these symptoms as they can be attributed to many many many other ailments either individually or in groups.

Also, some people tend to blame Chiari on everything they seem to suffer with. Remember that is is very possible to have more than one "something" going on in your body at the same time.

If you are unsure, then go and see your doctor, take some information about Chiari and Syringomyelia with you, because the odds are they haven't got a clue about it. If you are not happy with their diagnosis then don't be afraid to push a few buttons to get to see who you need to know. You may see that you have a long fight on your hands.

The main symptom of Chiari is a headache emanating from the back of the head and moving through the rest of your skull often reported as a pressure wave feeling.

Other symptoms can include the following:

The most common symptom of Chiari malformation is a headache, which begins at the back of the head (neck) and radiates upward. Often described as a "pressure wave" and can be brutally debilitating. The pain is often made worse or can be brought on by coughing, sneezing, laughing or straining.

Other symptoms can include:

Painful tension in neck
Fatigue
Migraines
Dizziness
Visual disturbances / loss of vision / spots in vision / double vision / seeing spots or “halos” / nystagmus
Tingling / numbness in the extremeties
General imbalance / clumsiness
Memory loss
Restricted movement
Intolerance to bright light / difficulty adjusting to light change
Vertigo from position change or sudden standing
Difficulty walking on uneven ground / feeling ground under feet
Poor / degraded motor skills
Difficulty driving
Difficulty negotiating steps
Pressure / pain in the neck
Pressure / pain behind the eyes (soreness in the eyeballs)
Back pain
Neck spasms
Insomnia
Ringing in ears (like the tone heard in a hearing test)
Swaying
Pain when changing position
Tingling / crawling feeling on scalp
Intolerance to loud / confusing sounds
Decreased sensation to touch in extremeties
Decreased sensitivity to temperature
Pain & tension along ear / eye / jawline
Difficulty swallowing / lump in throat / sore throat / swollen lymph nodes
Drooling
Spontaneous vertigo
Hand tremors
Poor blood circulation / cold hands & feet
Sinus / mucous problems
Sleep apnea
Decreased muscle tone
Pressure in ears / ears feel stopped up
Nausea
Difficulty reading / focusing on text
Depth perception problems
Burning sensation in extremeties / shoulder blades
Menstrual problems / severe cramping during period
Fluid-like sound in ears (like water running)
Loss of sexual interest / lack of sensation in pelvic area
Pulling sensation while sitting / standing
Intense itchiness w/profuse sweating
Slurred speech
Gag reflex problems / lack of gag reflex
Pressure / tightness in chest
Loss of bladder control
Frequent urination
Dehydration / excessive thirst
Electric like burning sensations
Unequal pupil size
Loss of taste
Popping / cracking sounds in neck or upper back when stretching
Loss of smell / problems with sense of smell
Dry skin and lips

Conquer Chiari in Amarica have posted some information about symptoms which is very interesting and also hi lights how we can all present different levels of symptom and symptom type, making it so difficult to diagnose at the best of times.

Table 1
Symptoms Reported By At Least 50% Of Patients

Symptom %

Headache 98
Dizziness 84
Difficulty sleeping 72
Weakness in arms/hands 69
Neck pain 67
Numbness/tingling in arm, hand 62
Fatigue 59
Nausea 58
Shortness of breath 57
Blurred Vision 57
Tinnitus 56
Difficulty swallowing 54
Leg weakness 52

Table 2
Symptoms Reported By Less Than 50% Of Patients

(20%-50%) - depression, body weakness, balance problem, memory problems, leg/foot numbness, hoarse voice, chest pain, facial numbness, anxiety, slurred speech, arm pain, abdominal pain, photophobia

(<20%) - tachycardia, trouble hearing, vomiting, double vision, word-finding problems, vision loss, blackouts, apnea, vertigo, loss of peripheral vision, nystagmus, earache, nosebleeds, snoring, thoracic pain, hypotension, wake up choking, leg pain, palpitations, hypertension, abnormal gag reflex, face pain/tingling

Source: Mueller DM, Oro' JJ. Prospective analysis of presenting symptoms among 265 patients with radiographic evidence of Chiari malformation type I with or without syringomyelia. J Am Acad Nurse Pract. 2004 Mar;16(3):134-8.

Other related links:
Glossary
Rare? or just uncommon?
Syringomyselia - What is it?